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Fig. l. Molluscous animal inclosing the Spirula Peronii. See V. I. p. 362.* (Blainville.)

Fig. 2. Section of a Spirula (Nat. size), shewing its transverse Plates and siphuncular sheath. (Original.)

* M. Robert has recently discovered between the Canaries and Cape Blanc, several imperfect bodies of a small species of molluscous animal, each inclosing a Spirula.

In all these the position of the shell is not at the posterior extremity, as in the figure of the specimen found by Peron, but in the back, parallel to the axis of the body, like the shell of the Sepiostaire, or internal shell of the common Sepia. This position agrees with that of the animal figured by Blainville, if we suppose the caudal portion of the latter to have been lost.

On each side of the body are two expansions that act like Fins, as in the Sepiole. Beneath the neck is the aperture of the Funnel. [064]

In one specimen the Eye is preserved, and is very large in proportion to the body. These Mollusks form the prey of the Physali, and were caught entangled in their Tentacula.
L'Echo du Monde Savant, I Mai, 1836.

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Fig. 3. Lituite in the Transition lime-stone of Oeland.
a. Siphuncle of Lituite. (Original.)

Fig. 4. Section of an Orthoceratite in the Transition lime-stone of Oeland, in the Collection of G. Stokes, Esq. (Original.)
a. Siphuncle of the same.

Fig. 5. Baculite, from Chalk of the Cotentin terminating at its large end in the chamber a. (Original.)

Fig. 5. b. Front view of the transverse plate of a Baculite, shewing the margin to be disposed in lobes and saddles, and the place of the Siphuncle  to be on the back of the shell at c. (Original.)

Fig. 6. Transverse section of a Nummulite. (Parkinson, V. 3. Pl. X. Fig. 16.)

Fig. 7. Longitudinal section of another Nummulite.* (Parkinson.)

* Among the microscopic fossil shells placed by D'Orbigny in the same Order as Nummulites (Foraminiféres), Count Munster enumerates 40 species from the Cretaceous free stone of Maestricht. Mr. Lonsdale also has discovered 16 species of microscopic foraminifers in the English Chalk. (See V. I. p. 448, Note.) Microscopic shells of this Order occur in countless myriads throughout the Tertiary strata. (See V. I. p. 385.)

The Sand of the Shores of the Adriatic, and of many Islands in the Archipelago, is crowded with recent microscopic shells of the same kind.

It is mentioned in our Note, V. I. p. 382, that doubts have arisen as to the supposed origin of many of these minute multilocular shells from Cephalopods. Some recent observations of M. Dujardin have induced him to refer the Animals which construct the Miliola and some other microscopic foraminiferous shells, to a new Class of animals of lower degree than the Radiata, and possessing a locomotive power by means of minute tentacular filaments He proposes to give them the name of Rhizopodes. Ann. des Sci. Nat. Mai, 1835, p. 312.

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Fig. 8. Hamites Bucklandi, (Phillips,) from the Gault or Speeton Clay, in the collection of Mr. I. Phillips, of York. (Original.)

Fig. 8^a. Transverse septum of Fig. 8, shewing the lobes and saddles, and the siphuncle at a.

Fig. 9. Hamites armatus, from the upper Green Sand, near Benson. (Sowerby.)

Fig. 10. Transverse section of the same, shewmg the siphuncle, on the back, between the spines.

Fig. 11. Hamites from Folkstone Clay, shewing the spiral Ribs of the outer shell. At a. we see the Siphuncle, and the lobes and saddles of the transverse Plate.

Fig. 12. Fragment of the cast of the interior of another Hamite from Folkstone Clay, shewing the Siphuncle at a. The removal of the outer shell shews the sinuous edges of the transverse Plates beneath the Ribs. (Original.)

Fig. 13. Fragment of Hamites articulatus (Sow.) from the Green Sand at Earl Stoke, shewing the Siphuncle (a.) covered by a small portion of the shell. The sinuous terminations of the transverse plates are visible beneath the ribs, having their secondary lobes rounded outwards (b.) and pointed inwards (c.) like the secondary lobes of Aminonites. (Original.)

Fig. 14 . Fragment of Turrilites Bergen, in the collection of G. B. Greenough, Esq. from the Green Sand formation. The siphuncle is seen near the upper or dorsal margin of two whorls at a. a.; the sinuous edges of the transverse plates are visible on the middle whorl; and the entire surface of a transverse plate is laid open at the smaller end of a third whorl, shewing its lobes and saddles to be analogous to the same parts in Ammonites. (Original.) [066]

Fig. 15. Scaphites Equalis, from Chalk near Rouen, in the collection of Mr. J. Sowerby; the sides of the external shell are strengthened and ornamented by ribs and tubercles; and the edges of the transverse plates disposed in sinuous foliations (c.) as in Ammonites. The mouth or outer margin (6.) returns so nearly into contact with the air chambers (c.), that the want of space at this part for the expansion of arms and head, makes it probable that the Scaphite was placed entirely within the body of its animal. (Original.)

Fig. 16. Transverse section of the chambered portion of Fig. 15, shewing the arrangement of the lobes and saddles to be similar to that of Ammonites; the siphuncle also is seen on the dorsal margin at a. (Original.)
Fig. 17. Longitudinal section of the calcareous Sheath and Alveolus of a Belemnite.
a. Alveolus, or internal shell, divided by transverse Septa into air chambers. See V. I. p. 373.
b. Siphuncle, passing along the margin of the air chambers.
c. Apex of the fibro-calcareous sheath, or solid Cone of the Belemnite.