Fig. l. Lepidosteus osseus, or bony Pike of North America. (Agassiz. Vol. 2. Tab. A.)

Fig. 2. Portion of the lower Jaw of Lepidosteus osseus, shewing the occurrence of a row of larger conical hollow teeth, fluted externally, between two rows of smaller Teeth. (Original.)

2. a. Longitudinal section of a large Tooth, shewing the internal hollow cone. (Original.)

2. b. Transverse section of a large Tooth. (Original.)

Fig. 3. Transverse section of the Jaw. fig. 2. (Original.)

Fig. 4. Fragment of a small upper Jaw of Megalichthys
Hibberti, from Burdie house, shewing a disposition
of large and small teeth, similar to that in fig. 2.
(Hibbert.)

4. a. b. Transverse section of the larger teeth.

4. c. Longitudinal section of a large Tooth.*

4. d. Punctate scale of Megalichthys.

Fig. 5. Aspidorhynchus: a fossil Sauroid fish from the Lime stone of Solenhofen. (Agassiz, Vol. l. Tab. F.)

* It appears that in the Megalichthys and Holoptychus the structure of the teeth, both large and small, was precisely the same as in the large and small teeth of Lepidosteus osseus, both as to the hollow internal conical cavity, and the external flutings towards the base, and also as to their mode of growth by ascent of fibrous matter from the bony substance of the jaw, and not from roots placed in deep alveoli, as in many of the Saurians.