of the



First Monograph

in Three Parts - I. Essay on Classification - II. North American Testudinata - III. The Embryology of the Turtle

With Thirty-Four Plates

Volume I and Volume II



643 + 51 pages +  34  plates and 11 woodcuts.

Dedication  v  v

Preface  vii  vii  viii  ix  x  xi  xii  xiii  xiv  xv  xvi







SECTION 1. The leading features of a natural zoological system are all founded in nature. 
003  004  005  006  007  008  009  010  011  012
There is but one system, and that is to be read in nature, and was not devised by man. The essential divisions of that system cannot be arbitrary, p. 3-12.

SECTION 2. Simultaneous existence of the most diversified types under identical circumstances.  
012  013  014  015  016
Organized beings of the most different structure are everywhere found together, p. 12-16.

SECTION 3. Repetition of identical types under the most diversified circumstances.  
016  017
Organized beings with the same structure occur in the most different parts of the world, p. 16-17.

[017] When naturalists have investigated the influence of physical causes upon living beings, they have constantly overlooked the fact that the features which are thus modified are only of secondary importance in the life of animals and plants, and that neither the plan of their structure, nor the various complications of that structure, are ever affected by such influences. What, indeed, are the parts of thw body which are, in any way, affected by external influences? Chiefly those which are in immediate contact with the external world, such as the skin... then the size of the body and its weight... the thickness of the shell of Mollusks, when they live in waters or upon a soil containing more or less limestone, etc.

SECTION  4. Unity of plan in otherwise highly diversifited types.  
018  019
The greatest diversity of form and of complication of stricture may be found under the same plan of structure, p. 18-19.

[018] Nothing is more striking throughout the animal and vegetable kingdoms than the unity of plan in the structure of the most diversified types.

SECTION 5. Correspondence in the details of structure in animals otherwise entirely disconnected.  
019  020  021
Animals, between which no genetic relation can be traced, may nevertheless exhibit the most astonishing correspondence in the details of their structure, p. 19-21.

[019] During the first decade of this century, naturalists began to study relations among animals which had escaped almost entirely the attention of earlier is only recently that anatomists have eiscovered the close correspondence which exists between all the parts of all animals belonging to the same type, however different they may appear at first sight. Not only is the wing of the bird identical in its structure with the arm of man, or the fore leg of a quadruped, it agrees quite as closely with the fin of the whale, or the pectoral fin of the fish, and all these together correspond in the same manner with their hind extremities. ...But this correspondence is not limited to the skeleton; every other system of organs exhibits in these animals the same relations, the same identity in plan and structure, whatever be the differences in the form of the parts....Such an agreement in the structure of animals is called their homology, and is more or less close in proportion as the animals in which it is traced are more or less nearly related.

SECTION  6. Various degrees and different kinds of relationship among animals. 
021  022  023
Animals differ from one another, not only in degree; there are also different kinds of differences, p. 21-23.

SECTION  7. Simultaneous existence in the earliest geological periods of all the great types of animals.  
023  024  025
The leading types of the animal kingdom have made their appearance upon the surface of our globe at the same time, p. 23-25.

[023] It was formerly believed by geologists and palaeontologists that the lowest animals first made their appearance upon this globe, and that they were followed by higher and higher types, until man crowned the series. Every geological museum, representing at all the present state of our knowledge, may now furnish the evidence that this is not the case. On the contrary, representatives of numerous families belonging to all the four great branches of the animal kingdom, are well known to have existed simultaneously in the oldest geological formations....[N]either Radiata, nor Mollusks, nor Articulata, have any priorit over thye other, as to the time of their first appearance upon earth...[F]ishes exist wherever Radiata, Mollusks, and Articulata are found together, and the plan of structure of these four great types constitutes a system intimately connected in its very essence... [T]he idea of a gradual succession of Radiata, Mollusks, Articulata, and Vertebrara, is for ever out of the question. It is proved beyond doubt, that Radiata, Mollusca, and Articulata are everywhere found together in the oldest geological formations, and that very early Vertebrata are associated with them, to continue together through all geological ages to the present time....

This is not all: every class among Radiata, Mollusks, and Articulata, is known to have been represented in those earliest days, with the exception of the Acalephs and Insects only. that the assumption of a successive introduction of these types upon earth is flatly contradicted by well established and well known facts.... But when we come to the orders, it can hardly be doubted that the gradation of these natural divisions among themselves in each class, constitutes the very essence of this kind of groups. [empahsis added -- dcb]

SECTION 8. The gradation of structure among animals. 
026  027  028  029  030
There is a gradation among animals, though they do not form one continuous series, p. 26-30.

SECTION  9. Range of geographical distribution of animals. 
030  031  032  033  034  035  036
The range of distribution of different kinds of animals is very unequal. Faunie, p. 30-36.

[032] [V]arious animals and plants were respectively adapted with all the peculiarities of their kingdom, those of their class, those of their order, those of their genus, and those of their species, to the home assigned to them, and therefore, not produced by the nature of the place, or of the element, or any other physical condition....In other words, in all these animals and plants, there is one side of their organization which has an immediate reference to the elements in which they live, and another which has no such connection, and yet it is preciselythis part of the structure of animals and plants, which has no direct bearing upon the conditions in which they are placed in nature, which constitutes their essential, their typical character. this proves beyond the possibility of an objection, that the elements in which animals and plantes live (and under this expression I mean to include all that is commonly called physical agents, physical causes, etc.,) cannot in any way be considered as the cause of their existence.

SECTION 10. Identity of structure of widely different types. 
036  037  038  039  040
Animals found within entirely disconnected areas may have the same structure, p. 36-40.

[039] [M]ore extensive and precise knowledge of the geographical distribution of organized beings forced upon its cultivators the conviction, that neither animals nor plants could have originated upon one and the same spot upon the surface of the earth, and hence have spread more and more widely until the whole globe became inhabited. It was really an immense progress which freed science from the fetters of an old prejudice. ... But even to grant distinct centres of distribution for each species within their natural boundaries, is only to meet the facts half way, as there are innumerable relations between the animals and plants which we find associated everywhere, which must be considered as primitive, and cannot be the result of successive adaptation....Pines have originated in forests, heaths in heathers, grasses in prairies, bees in hives, herrings in schools, buffaloes in herds, men in nations! .

[040] I confess that nothing has ever surprised me so much as to see the perfect identity of the most delicate microscopic structures of animals and plants, from the remotest parts of the world. It was this striking identity of structure in the same types, this total independence of the essential characteristics of animals and plants, of their distribution under the most extreme climatic differences known upon our globe, which led me to distrust the belief, then almost universal, that organized beings are influenced by physical causes to a degree which may essentially modify their character.

SECTION 11. Community of structure among animals living in the same regions.  041  042  043
Animals occupying the same region exhibit sometimes a remarkable similarity of structure, p. 41-43.

SECTION 12. Serial connection in the structure of animals widely scattered upon the surface of our globe. 
043  044  045  046  047
Animals living in different parts of the world form frequently series which are closely linked together, p. 43-47.

SECTION 13. Relation between the size of animals and their structure.  047  048  049
Though apparently of secondary importance, the size of animals bears a definite relation to their trueture, p. 47-49.

SECTION 14. Relation between the size of animals and the mediums in which they live. 
049  050
There is also a definite relation between the size of animals and the mediums in which they live, p. 49-50.

SECTION 15. Permanency of specific peculiarities in all organized beings. 
051  052  053  054  055  056
Immutability of species. p. 51-56.

SECTION 16. Relations between animals and plants and the surrounding world. 
057  058  059  060  061  062  063
There exist definite relations between the animals and plants, and the conditions under which the live. Habits of animals. p. 57-63.

SECTION 17. Reiations of individuals to one another. 
063  064  065  066
The relations in which individual animals stand to one another are well defined in nature, p. 63-66.

SECTION 18. Metamorphoses of animals. 
066  067  068  069  070  071  072  073  074  075  076  077  078  079  080  081  082  083  084  085  086  087  088
Importance of Embryology. Works upon this subject. Polypi, Acalephs, Echinoderms, Classes of Radiata. Mollusks, their affinities and development. Articulata, their range and affinities. Worms, Crustacea, Insects. Vertebrata. Embryology furnishes standards to determine the relative rank among animals. Distinction between homologies and analogies. Independence of the development of animals from external causes. p. 66-88.

[068] The universal presence of eggs in all animals and the unity of their structure ... constitute, in my opinion, the greatest discovery of modern times in the natural sciences.

SECTION 19. Duration of Life. 
088  089
There is the greatest diversity in the average duration of the life of different kinds of animals, p. 88-89.

SECTION 20. Alternate generations. 
090  091  092  093
There are animals the successive generations of which are not identical, though their diflrences are circumscribed within definite cycles, p. 90-93.

SECTION 21. Succession of animals and plants in geological times. 
098  099  100  101
The succession of organized beings in past geological ages exhibits biological phenomena of the most complicated nature, requiring an extensive acquaintance with Zoölogy, Comparative Anatomy, and Embryology, to be rightly appreciated. Works relating to the fossil remains of different classes and of different geological periods. Difference between the organic and inorganic kingdoms. p. 98-101.

[094] What amount of labor  and patience it has cost only to establish the fact, that fossils are really the remains of animals and plants that once actually lived upon earth...Then it had to be proved, that they are not the wrecks of the Mosaic deluge, which, for a time was the prevailing opiniion, even among scientific men. After Cuvier had shown, beyond question, that they are the remains of animals no longer to be found upon the earth, among the living, Palaeontology acquired for the first time a solid basis. Yet what amount of labor it has cost to ascertain, by direct evidence, how these remains are distributed in the solid crust of our globe, what are the differences they exhibit in successive formations, what is their geographical distribution! ...One result, however, stands now unquestioned: the existence during each great geological era of an assemblage of animals and plants differing essentially for each period.

SECTION 22. Location of types in past ages. 
102  103
The geographical distribution of some types of animals was circumscribed within similar limits in past ages and now, p. 102-103.

SECTION 23. Limitation of species to particular geological periods. 
104  105  106
Not only species, but all other groups of animals and plants, have a definite range or duration, p.104-106.

SECTION 24. Parallelism between the geological succession of animals and plants and their present relative standing. 
107  108  109  110  111  112
The relative rank or the animals now living coincides with the order of succession of their representatives in past ages p.107-112.

[107] The total absence of the highest representatives of the animal kingdom in the oldest deposits forming part of the crust of our globe, has naturally led to the very general belief, that the animals which have existed during the earliest period of the history of our earthy were inferior to those now living, nay, that there is a natural gradation from the oldest and lowest animals to the highest now in existence. to some extent this is true; but it is certainly not true that all animals form one simple series from the earliest times, during which only the lowest types of animals would have been represented, to the last period, when Man appeared at the head of the animal creation.

SECTION 25. Parallelism between the geological succession of animals and the embryonic growth of their living representatives. 
112  113  114  115  116
The changes which animals undergo during their embryonic growth coincide also with the order of succession of the fossils of the same types in past ages.  p. 112-116.

[115] It may be considered as a general fact, that the phases of development of all living animals correspond to the order of succession of their extinct representatives in past geological times. As far as this goes, the oldest representatives of every class may then be considered as embryonic types of their respective orders or families among the living

SECTION 26. Prophetic types among animals. 
116  117  118
Distinction between prophetic, pregressive and synthetic types. A deeper insight into these relations is indespensable in order to appreciate the succession of' organized beings in past times, p. 116-118.

SECTION 27. Parallelism between the structural gradation of animals and their embryonic growth. 
118  119  120
The phases of development of animals coincide with the different levels in the gradation of their respective types. p. 118-120.

SECTION 28. Relations between the structure, embryonic growth, geological succession, and the geographycial distribution of animals. 
120  121  122
The geographical distribution of animals upon the surface of the globe bears direct relations to the rank, the embryonic growth, and the geological succession of their respective types, p. 120-122.

SECTION 29. Mutual dependence of the animal and vegetable kingdoms.  
122  123
The animal and vegetable kingdoms are dependent upon one another, and stand in harmonious relation. p. 122-123.

SECTION 30. Parasitic animals and plants. 
123  124  125  126  127
Various degrees and difl'erent kinds of parasitism among animals and plants. Parasites do not form natural groups p. 123-127.

SECTION 31. Combination in time and space of curious kinds of relations among animals. 
127  128  129  130  131
There a striking relation between the rank of animals. their embryonic growth, their geological  succession, and their geographical distribution, but even etween organized
beings and some of the members of our solar system. p. 127-131.

SECTION 32. Recapitulation. 
132  133  134  135  136
Bearing of the points considered in the preceding Sections upon the question of the origin of organized beings. What Classification should be. p. 132-136.


1st. The connection of all these known features of nature into one system exhibits thought, the most comprehensive thought, in limits transcending the highest wonted powers of man.

2d. The simultaneous existence of the most diversified types under identical circumstances exhibits thought, the ability to adapt a great variety of structures to the most uniform conditions.

3d. The repetition of similar types, wider the most diversified circumstances, shows an immaterial connection between them; it exhibits thought, proving directly how completely the Creative Mind is independent of the influence of a material world.

4th. The unity of plan in otherwise highly diversified types of animals, exhibits thought; it exhibits more immediately premeditation, for no plan could embrace such a diversity of beings, called into existence at such long intervals of time, unless it had been framed in the beginning with immediate reference to the end.

5th. The correspondence, now generally known as special homologies, in the details of structure in animals otherwise entirely disconnected, down to the most minute peculiarities, exhibits thought, and more immediately the power of expressing a general proposition in an indefinite number of ways, equally complete in themselves, though differing in all their details.

6th. The various degrees and different kinds of relationship among animals which can have no genealogical connection, exhibit thought, the power of combining different categories into a permanent, harmonious whole, even though the material basis of this harmony be ever changing.

7th. The simultaneous existence, in the earliest geological periods in which animals existed at all, of representatives of all the great types of the animal kingdom exhibits most especially thought, considerate thought, combining power, premeditation, prescience, omniscience.

8th. The gradation based upon complications of structure which may be traced among animals built upon the same plan, exhibits thought, and especially the power of distributing harmoniously unequal gifts.

9th. The distribution of some types over the most extensive range of the surface of the globe, while others are limited to particular geographical areas, and the various combinations of these types into zoölogical provinces of unequal extent, exhibit thought, a close control in the distribution of the earth's surface among its inhabitants.

10th. The identity of structure of these types, notwithstanding their wide geographical distribution, exhibits thought, that deep thought which, the more it is scrutinized, seems the less capable of being exhausted, though its meaning at the surface appears at once plain and intelligible to every one.

11th. The community of structure in certain respects of animals otherwise entirely different, but living within the same geographical area, exhibits thought, and more particularly the power of adapting most diversified types with peculiar structures to either identical or to different conditions of existence.

12th. The connection, by series, of special structures observed in animals widely scattered over the surface of the globe, exhibits thought, unlimited comprehension, and more directly omnipresence of mind, and also prescience, as far as such series extend through a succession of geological ages.

13th. The relation there is between the size of animals and their structure and form, exhibits thought; it shows that in nature the quantitative differences are as fixedly determined as the qualitative ones.

14th. The independence, in the size of animals, of the mediums in which they live, exhibits thought, in establishing such close connection between elements so influential in themselves and organized beings so little affected by the nature of these elements.

15th. The permanence of specific peculiarities under every variety of external influences, during each geological period, and under the present state of things upon earth, exhibits thought: it shows, also, that limitation in time is an essential element of all finite beings, while eternity is an attribute of the Deity only.

16th. The definite relations in which animals stand to the surrounding world, exhibit thought; for all animals living together stand respectively, on account of their very differences, in different relations to identical conditions of existence, in a manner which implies a considerate adaptation of their varied organization to these uniform conditions.

17th. The relations in which individuals of the same species stand to one another, exhibit thought, and go far to prove the existence in all living beings of an immaterial, imperishable principle, similar to that which is generally conceded to man only.

18th. The limitation of the range of changes which animals undergo during their growth, exhibits thought; it shows most strikingly the independence of these changes of external influences, and the necessity that they should be determined by a power superior to these influences.

19th. The unequal limitation in the average duration of the life of individuals in different species of animals, exhibits thought; for, however uniform or however diversified the conditions of existence may be under which animals live together, the average duration of life, in different species, is unequally limited. It points, therefore, at a knowledge of time and space, and of the value of time, since the phases of life of different animals are apportioned according to the part they have to perform upon the stage of the world.

20th. The return to a definite norm of animals which multiply in various ways, exhibits thought. It shows how wide a cycle of modulations may be included in the same conception, without yet departing from a norm expressed more directly in other combinations.

21st. The order of succession of the different types of animals and plants characteristic of the different geological epochs, exhibits thought. It shows, that while the material world is identical in itself in all ages, ever different types of organized beings are called into existence in successive periods.

22d. The localization of some types of animals upon the same points of the surface of the globe, during several successive geological periods, exhibits thought consecutive thought; the operations of a mind acting in conformity with a plan laid out beforehand and sustained for a long period.

23d. The limitation of closely allied species to different geological periods, exhibits thought; it exhibits the power of sustaining nice distinctions, notwithstanding the interposition of great disturbances by physical revolutions.

24th. The parallelism between the order of succession of animals and plants in geological times, and the gradation among their living representatives, exhibit thought; consecutive thought, superintending the whole development of nature from beginning to end, and disclosing throughout a gradual progress, ending with the introduction of man at the head of the animal creation.

25th. The parallelism between the order of succession of animals in geological times and the changes their living representatives undergo during their embryological growth, exhibits thought; the repetition of the same train of thoughts in the phases of growth of living animals and the successive appearance of their representatives in past ages.

26th. The combination, in many extinct types, of characters which, in later ages appear disconnected in different types, exhibits thought, prophetic thought, foresight; combinations of thought preceding their manifestation in living forms.

27th. The parallelism between the gradation among animals and the changes they undergo during their growth, exhibits thought, it discloses everywhere the most intimate connection between essential features of animals which have no necessary physical relation, and can, therefore, not be understood otherwise than as established by a thinking being.

28th. The relations existing between these different series and the geographical distribution of animals, exhibit thought; they show the omnipresence of the Creator.

29th. The mutual dependence of the animal and vegetable kingdoms for their maintenance, exhibits thought; it displays the care with which all conditions of existence, necessary to the maintenance of organized beings, have been balanced.

30th. The dependence of some animals upon others or upon plants for their existence, exhibits thought; it shows to what degree the most complicated combinations of structure and adaptation can be rendered independent of the physical conditions which surround them.

We may sum up the results of this discussion, up to this point, in still fewer words: -

All organized beings exhibit in themselves all those categories of structure and of existence upon which a natural system may be founded, in such a manner that, in tracing it, the human mind is only translating into human language the Divine thoughts expressed in nature in living realities.

All these beings do not exist in consequence of the continued agency of physical causes, but have made their successive appearance upon earth by the immediate intervention of the Creator. As proof, I may sum up my argument in the following manner:

The products of what are commonly called physical agents are everywhere the same, (that is, upon the whole surface of the globe,) and have always been the same (that is, during all geological periods); while organized beings are everywhere different and have differed in all ages. Between two such series of phenomena there can be no causal or genetic connection.

31st. The combination in time and space of all these thoughtful conceptions exhibits not only thought, it shows also premeditation, power, wisdom, greatness, prescience, omniscience, providence. In one word, all these facts in their natural connection proclaim aloud the One Cod, whom man may know, adore, and love; and Natural History must, in good time, become the analysis of the thoughts of the Creator of the Universe, as manifested in the animal and vegetable kingdoms.

It may appear strange that I should have included the preceding disquisition in that part of my work which is headed Classification. Yet, it has been done deliberately. In the beginning of this chapter, I have already stated that Classification seems to me to rest upon too narrow a foundation when it is chiefly based upon structure. Animals are linked together as closely by their mode of development, by their relative standing in their respective classes, by the order in which they have made their appearance upon earth, by their geographical distribution, and generally by their connection with the world in which they live, as by their anatomy. All these relations should, therefore, be fully expressed in a natural classification; and though structure furnishes the most direct indication of some of these relations, always appreciable under every circumstance, other considerations should not be neglected, which may complete our insight into the general plan of creation.

In characterizing the great branches of the animal kingdom, it is not enough to indicate the plan of their structure, in all its peculiarities; there are possibilities of execution which are at once suggested to the exclusion of others, and which should also be considered, and so fully analyzed, that the various modes in which such a plan may be carried out shall at once be made apparent. The range and character of the general homologies of each type should also be illustrated, as well as the general conditions of existence of its representatives. In characterizing classes, it ought to be shown why such groups constitute a class and not merely an order, or a family; and to do this satisfactorily, it is indispensable to trace the special homologies of all the systems of organs which are developed in them. It is not less important to ascertain the foundation of all the subordinate divisions of each class; to know how they differ, what constitutes orders, what families, what genera, and upon what characteristics species are based in every natural division.



SECTION 1. Great types or branches of the animal kingdom. 
137  138  139  140  141  142  143  144
Attempt to define the fundamental divisions of the animal kingdom. Early classifications. Comparison of' the writings of different authors with the view of determining what are natural groups among animals. The great branches of the animal kingdom are characterized by the plan of their structure. p. 137-144.

>Branches of the Animal Kingdom: Radiata, Molusca,
Articulata, Vertebrata

SECTION 2. Classes of animals. 
145  146  147  148  149  150
Classes are natural divisions, characterized by the manner in which the plan of their respective great types is executed, and by the means employed in the execution. Structure considered in different points of view. p. 145-150.

[145] Structure may be considered from many points of view: first, with reference to the plan adopted in framing it; secondly, with reference to the work to be done by it, and to the ways and means employed in building it up; thirdly, with reference to the degrees of perfection or complication it exhibits; fourthly, with reference to the form of the whole structure and its parts; fifthly, with reference to its last finish, to the execution of the details in the individual parts.

[147] Classes of Radiata: Polypi - the body exhibits a large cavity divided by radiating partitions into a number of chambers, into which hangs a sac (the digestive cavity,) open below, whence it is circulated to and fro in all the chambers, by the agency of cilia; Acalephs - the body is plain and full not to be compared to a hollow sac, traversed only in its thickness by radiating tubes, which arise from a central cavity (the digestive cavity); Echinoderms - there is a tough or rigid envelope to the body, inclosing a large cavity in which are contained a variety of distinct systems of organs.

SECTION 3. Orders among animals. 
150  151  152  153  154  155 
Orders are natural groups founded upon the degree of complication of the structure. Relative rank or standing among animals. p. 150-155.

SECTION 4. Families. 
155  156  157  158  159  160  161
Families are natural groups founded upon the form of animals. Indefinite use thus far made of the form in characterizing animals. Importance of greater precision in that respect. p. 155-161.

SECTION 5. Genera.  Linnaeus' view of genera. Latreille.
161 162  163
Genera are natural groups based upon the ultimate details of structure. p. 161-163.

SECTION 6. Species. 
163  164  165  166  167  168  169  170
Generally but wrongly based upon fecundity. Hybridity, individuality, alternate generation, polymorphism. Species exist in nature in the same manner as any other natural groups; they are based upon well determined relations of individuals to one another and to the world around them, and upon the proportions, the ornamentation, and the relations of their parts, p. 163-170.

SECTION 7. Other natural divisions among animals. 
170  171  172
Besides branches, classes, orders, families, genera, and species, which express the fundamental categories of the existence of' animals, there occur here and there further natural subdivisions, p. 170-172.

[170] Branches: plan of their structure; Classes: manner in which the plan is executed; Orders: degrree of complication of the structure; Family: Form of the structure; Genera: Details of execution of special parts; Species: relation of individuals to one another and to the environment, and proportions of their parts, ornamentation, etc. Suclass: One system of organs has a peculiar development while other systems coincide. (Marsupials contr. Placental Mammals).

SECTION 8. Successive development of characters. 
172  173  174  175  176
In the development of animals, the characteristic features do not appear in the order of their systematic dignity. Their succession still requires careful study. p. 172-176.

SECTION 9. Conclusions. 
177  178
Classification is a philosophical study of the greatest importance, p. 177-178.



SECTION 1. General remarks upon modern systems. 
179  180  181  182  183  184  185  186  187
Their aim and discrepancies. Desirable improvements. Limits of the fundamental divisions with their respective classes. Rhiizopoda and infusoria. Radiata, with three classes; Mollusks, with three classes; Articulata, with three classes; Vertebrata, with eight classes. p. 179-187.

SECTION 2. Early attempts to classify animals. 
187  188  189
Leading groups recognized by Aristotle, p. 187-189.

SECTION 3. Period of Linnaeus. 
189  190  191  192
Linnaeus was the first to present a definite system as expressing the natural affinities among animals, p. 189-192.

SECTION 4. Period of Cuvier, and anatomical systems. 
193  194  195  196  197  198  199  200  201  202  203  204  205  206  207  208  209  210
Four types among animals first recognized by Cuvier, p. 193. Classification of Cuvier, p. 194. Irregularities of this system, p. l95. Classification of Lamarck, p. 196. Its principle, p. 197. Classification of DeBlainville, p. 198. Compared with those of Lamarck and Cuvier, p. 199. Classification of Ehrenherg, p. 200. Its principle, p. 201. Classification of Burmeistor, p. 203. Classification of Owen, p. 204. Compared with those of Cuvier and von Siebold, p. 205. Growing resemblance of modern systems, p. 206. Classification of Milne Edwards, p. 207. Classification of von Siebold, and Stannius, p. 208. Classification of Leuckart, p. 209. General remarks upon anatomical classifications, p. 210.

SECTION 5. Physiophilosophical systems.  Oken's views and influence upon the progress of Zoölogy, p. 211. 
211  212  213  214  215  216  217  218  219  220
His classification, p. 212. Classification of Fitzinger, p. 214. Classification of McLeny, p. 216. Affinity and analogy, p. 216-220.

SECTION 6. Embryological systems. 
220  221  222  223  224  225  226  227  228  229  230  231  232  233  234
Influence of Düllinger, p. 220. K. E. von Baer as systematic writer, p. 220-226. His classification, p. 226. Classification of Van Beneden, p. 227. Diagram of the development of animals by Kölliker, p. 229. Classification of Vogt, p. 280. Further advance in perfecting the system of zoölogy is chiefly to be expected from embryological investigations.





SECTION 1. Rank of the Testudinata. 
235  236  237  238  239  240
The Testutlinata constitute an order in the class of Reptiles. The plan of structure of the Vertebrata. Natural limits of the class of Reptiles. p. 235-240.

>Testudinata = Chelonians

SECTION 2. Special classification of Testudinata. 
241  242  243  244  245  246  247  248  249  250  251  252
The Testudinata constitute two sub-orders, which embrace several natural families, p. 241-252.

SECTION 3. Essential characters of the order of
Testudinata252  253  254  255
Their essential character lies not so much in their shield, as in the special development of the different regions of the body, which assigns to them the highest rank in their class, p. 252-255.

SECTION 4. The Shield. 
255  256  257
The shield consists of parts of the true skeleton, and of ossifications of the skin, or rather of the walls of the body, which overlie the true skeleton, p. 255-257.

SECTION 5. The Skin. 
257  258  259  260  261  262  263  264  265  266
The epidermis, p. 257. The colors in Turtles, p. 261. The cerium, p. 263.

SECTION 6. The Skeleton. 
266  267  268  269  270
Head, p. 266. Vertebrae, p. 266. Ribs, p. 267. Sternum, p. 267. Limbs, p. 267.

SECTION 7. The Muscles, p. 270. 
270  271  272  273  274

SECTION 8. The Nervous System, p. 274. 
274  275  276  277

SECTION 9. The Organs of the Senses. 
277  278
The ear, p. 275. The eye, p. 276. The nose, p. 276. The tongue and mouth, p. 277.

SECTION 10. Eating, Drinking, and Digestive Apparatus, p. 278. 
278  279  280  281

SECTION 11. 7'he Respiration, p. 281. 
281  282  283  284  285
Table showing the capacity of the lungs compared with the weight of the body, p. 283.

SECTION 12. The Vascular System, p. 285. 
285  286  287

SECTION 13. The Urogenital Organs. 
287  288  289  290
Urinary organs. p. 287. Genital organs, p. 287.

SECTION 14. The development of Turtles from a zoölogical point of view, p. 290. 
290  291  292  293  294  295  296
Table showing the successive changes in the relative dimensions of the body in Embridoidio, p. 292.

SECTION 15. The psychological development of Turtles compared with that of the other orders of Reptiles. 
296  297  298  299  300  301
Too little attention is now paid to the faculties of animals, p. 296.

SECTION 16. Geographical distribution of the
Testudinata.  301  302  303
Great discrepancy between the range of marine Turtles compared with that of the land and fresh water types, p. 301.

SECTION 17. First appearance of
Testudinata upon our globe, p. 303.  303  304  305  306  307  308
Table showing the period of the first appearance of the 'Testudinata compared with that of the other animals, p. 306.

SECTION 18. Suborders of
Testudinata308  309  310  311  312 
The suborders of sea Turtles, Chelonii, p. 308. The suborder of fresh water and land Turtles, Amydae, p. 310.

SECTION 19. Conclusions. 
313  314  315  316  317  318
Ordinal characters are essentially anatomical characters, and not what are commonly called zoölogical characters, p. 318.



SECTION 1. General remarks upon families. 
318  319  320
The method generally adopted in limiting families is defective. To arrive at satisfactory results, it is necessary to ascertain by careful comparisons what are the structural elements which constitute the different patterns of the families. p. 318-320.

SECTION 2. The family of Sphargididae, p. 320. 
320  321  322  323  324

SECTION 3. The family of Chelonioidae, p. 324. 
324  325  326  327  328  329

SECTION 4. Tics family of Trionychidae, p. 329. 
329  330  331  332  333  334  335

SECTION 5. The family of Chelyoidae, p. 335. 
335  336  337  338  339  340  341
The Sternotheroidae, Pelomedusae, Hydraspides, Chelodinoidae, and Podoenemides, note, p. 389.

SECTION 6. The family of Chelydroidae, p. 341. 
341  342  343  344

SECTION 7. The family of Cinosternoidae, p. 344. 
344  345  346  347  348  349  350  351

SECTION 8. The family of Emydoidae, p. 351. 
351  352  353  354  355  356
Subfamilies: Nectomydoidae, Deirocholyoidae, Evemydoidae, Clemmydoidae, Cistudinina, p. 355-356.

SECTION 9. The family of Testudinina, p. 356. 
356  357  358  359  360  361  362

SECTION 10. On the brain of the different families of North American Turtles.
The brain is typical for different families among Vertebrata. p. 362.  362  363  364  365

SECTION 11. Differences in the mode of life of Testudinata. 
365  366  367
The natural limits of families do not always coincide with the mode of life of their representatives. p. 365.



SECTION 1. General remarks upon the North American genera and species of Testudinata. 
367  368  369  370  371
How the genera of Testudinata ought to be characterized, and how they compare with genera in other classes, p. 367.

SECTION 2. The genus Sphargis, p. 371. 
371  372  373  374  375
Sphargis coriacea, p. 373. Identification and range of distribution of the species, p. 373.

SECTION 3. The genera and species of Chelonioidae, p. 375. 
375  376  377  378  379  380  381  382  383  384  385  386
Chelonia, p. 877. Chelonia Mydas, p. 378. Chelonia virgata, p. 379. Eretmochelys, p. 380. Eretmochelys imbricata, p. 381. Eretmochelys squamata, p. 382. Thalassochelys, p. 383. Thalassochelys Caouana, p. 384.

SECTION 4. Comparison of the growth of the Chelonii with that of the Amyde, p. 386. 
386  387  388  389  390  391  392  393  394

SECTION 5. The genera of Trionychidae, p. 394. 
394  395  396  397  398  399  400  401  402  403  404  405  406  407  408  409  410
Amyda, p. 898. Amyda mutica, p. 399. Platypeltis, p. 400. Platypeltis ferox, p. 401. Aspidonectes, p. 403. Aspidonectes spinifer, p. 403. Aspidonectes asper, p. 405. Aspidonectes nuchalis, p. 406. Aspidonectes Emoryi, p. 407.

SECTION 6. The genera of
Chelonioidae, p. 410.  410  411  412  413  414  415  416  417  418
Gypochelys, p. 413. Gypochelys lacertina, p. 414. Chelydra, p. 416. Chelydra serpentino, p. 417.

SECTION 7. The genera of Cinosternoidae, p. 418.  
418  419  420  421  422  423  424  425  426  427  428  429  430
Sub-family of Ozothecoidae, p. 423. Goniochelys, p. 423. Goniochelys triquctra, p. 423. Goniochelys minor, p. 424. Ozotheca, p. 424. Ozotheca odorata, p. 425. Ozotheca tristycha, p. 425. Subfamily of Cinosternoidae, p. 426. Cinosternum, p. 426. Thyrosternum, p. 427. Thyrosternum pennsylvanicum, p. 428. Thyrosternum sonoriense, p. 428. Thyrosternum integrum, p. 429. Platythyra, p. 429. Platythyra flavescens, p. 430.

SECTION 8. The genera of Emydoidae, p. 430. 
430  431  432  433  434  435  436  437  438  439  440  441  442  443  444  445  446
Sub-family of Nectemydoidae, p. 431. Ptychemys, p. 431. Ptychemys rugosa, p. 431. Ptychemys concinna, p. 432. Ptychemys mobiliensis, p. 433. Ptychemys hieroglyphica, p. 434. Ptychemys decussata, p. 434. Trachemys, p.434. Trachemys scabra, p. .134. Trachemys Troostii, p. 485. Trachemys elegans, p. 435. Trachemys rugosa, p. 436. Graptemys, p. 436. Graptemys geographica, p. 436. Graptemys LeSueurii, p. 436. Malacoclemmys, p. 437. Malacoclemmys palustris, p. 437. Chrysemys, p. 438. Chrysemys picta, p. 438. Chrysemys marginata, p. 439, Chrysemys Bellii, p. 439, Chrysemys Oregonensis, p. 440. Chrysemys Dorsalis, p. 440. Sub-family of the Deirochelyoidae, p. 441. Deirochelys reticulata, p. 441. Genera of the sub-family of Evemydoidae, p. 441. Emys, p. 441. Emys meleagris, p. 442. Genera of the Subfamily of Clemmydoidae. p. 442. Nanemys, p. 442, Nanemys Guttata, p. 442. Calemys, p. 443. Calemys Mühlenbergh, p. 443. Glyptemys, p. 443. Glyptemys insculita, p. 443. Actinemys, p. 444. Actinemys marmorata, p. 444. The sub-family of Cistudinina. p. 444. Cistudo, p. 444. Cistudo virginea, p. 445. Cistudo Triunguis, p. 445. Cistudo genata, p. 445, Cistudo major, p. 445.

SECTION 9. The Genera of Testudinina., p. 446. 
446  447  448  449
Xerobates, p. 446. Xerobates ca rolinus, p. 447. Xerobates berlandieri, p. 447, Chelonoidis, p. 448. Megalochelys, p. 448.

SECTION 10. Chelonian Faunae of North America. p. 449-450b.  449a 450b 451c 452d
The North-eastern Fauna p. 450b, The Western Fauna. p. 450b.  The Southern Fauna p. 451c. The Mexican Fauna p. 452d. The California Fauna p. 452d.






SECTION 1. The Origin of the Egg. p. 451.  451  452  453  454  455  456  457  458

SECTION 2. The Development of the Yolk. p. 458   458  459  460  461  462  463

SECTION 3. The Development of the Yolk Cells. p. 463.  463  464  465  466  467  468  469  470  471  472  473  474  475
Formation of the Ectoblast. p. 463. Formation of the Mesoblast. p. 467. Formation of the Ectoblast. p. 472.

SECTION 4. The Purkinjean Vesicle. p. 475.  475  476  477  478  479

SECTION 5. The Growth of the Ovarian Egg, as a Whole. p. 479.  479  480  481  482

SECTION 6. The Graafian Follicle, and the Membranes of the Egg. p. 482.  482  483  484  485  486  487  488 
The Stroma. p. 482. The Tunica granulosa. p. 483. The Zona pellucida. p. 484. The Vitelline Sac. p. 485. The Embryonic Membrane. p. 486.

SECTION 7. Fecundation. p. 489.  489  490  491  492  493  494  495  496  497  498



SECTION 1. The laying of the eggs.  498  499  500  501
Importance of local information respecting the habits of animals. The inhabitants of the country have much knowledge upon this subject that is not yet recorded. Period of laying. Passage of the eggs through the oviduct. Turtles lay only once a year. p. 498-501.

SECTION 2. Deposition of the albumen and formation of the shell.  501  502  503  504  505  506  507  508  509  510 
The albumen and shell membrane, p. 501-507. The shell, p. 508.

SECTION 3. The absorption of albumen into the yolk sac. 
511  512  513  514  515 
The albumen is gradually absorbed into the yolk sac, p. 511-513. This also takes place in birds' eggs, p. 513.

SECTION 4. The transformations of the yolk in the fecundated egg. 
516  517  518  519  520  521  522  523
Enlargement of the mesoblast, p. 516. Sudden multiplication of the entoblasts, p. 517. Segmentation of the mesoblast, p. 517. It results in the formation of the primitive cellular basis of the germ, p. 522.

SECTION 5. Segmentation of the yolk. 
523  524  525  526  527  528
The segmentation of the yolk takes place during the passage of the egg through the oviduct. The embryonic disc and the germinal layer. p. 523-528.

SECTION 6. The whole egg is the embryo. 
528  529  530  531  532  533  534
There is no natural limit between the development of the embryo, from its first appearance as egg to the formation of a distinct germ, and its ultimate growth.  Continuity of the genetic process, p. 528-534.

SECTION 7. Foldings of the embryonic disc, and successive stages of growth q( the Turtle. 
535  536  537  538  539  540  541  542  543  544  545  546  547  548  549  550  551  552  553  554  555  556  557  558  559  560  561  562  563  564  565  566  567  568  569  570  571  572  573  574  575  576  577  578
The embryonic disc, p. 535. The amnios, p. 536. Growth of the embryo, p. 542-578.

SECTION 8. Formation and development of the organs. 
579  580  581  582  583  584  585  586  587  588  589  590  591  592  593  594  595  596  597  598  599  600  601  602
The brain, p. 579. The ehorda dorsalis, p. 584. The eye, p. 584. The ear, p. 590. The nostrils, p. 591. The vertebral column, p. 591. The skull, p. 592. The shield, p. 592. The limbs, p. 593. The heart, p. 594. The bloodvessels, p. 597. The intestine, p. 600.

SECTION 9. Histology. 
602  603  604  605  606  607  608  609  610  611  612  613  614  615  616  617  618
The amnios, p. 602. The spinal marrow, p. 602. The medulla oblongata, p. 602. The hemispheres, p. 602. The olfactory lobes, p. 608. The olfactory nerve, p. 603. The Schneiderian membrane, p. 604. The pia mater, p. 604. The chorda dorsalis, p. 604. The vertebrae, p. 605. The ribs, p. 606. The limbs, p. 607. The skin, p. 608. The eye, p. 609. The ear, p. 611. The intestine, p. 611. The allantois, p. 613. The urinary bladder, p. 614. The lungs, p. 614. The trachea, p. 615. The liver, p. 615. The gall cyst, p. 615. The bloodvessels, p. 615. The genital organs, p. 615. The kidneys, p. 615. The Wolffian bodies, p. 616. The blood, p. 616. The muscles, p. 617. The tendons, p. 618.

SECTION 10. Chronology of the development of the embryo. 
618  619  620  621  622
From the first segmentation of the yolk to the period of hatching, we trace thirty-one stages of development, p. 618-622.

623  624  625  626  627  628  629  630  631  632  633  634  635  636  637  638  639  640

641  642  643


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