10 



VEETEBRATA. 



No. 20. 



Trogontherium Cuvieri, Fisch. 



Lower Jaw, right ramus. "Tins 

 ■magnificent relic of the gigantic Beaver," 



as Owen calls it, was taken out of a Incus- 

 trine deposit of clay and reddish sand 

 (Pliocene) at Ostend, on the coast of Nor- 

 folk, Eng. The chisel-crowned incisor 

 measures seven inches on the outer curve, 

 and is larger and stronger in proportion than in the existing Beaver; the outer 

 enamelled part is more convex, and the inner surface is concave, while in the 

 existing and fossil Beavers it is flat. The three anterior molars are also repre- 

 sented in situ. This fossil is preserved in the British Museum. 



Size, 8x6. Price, $2.00. 



No. 81, Castoroides Ohioensis, Foster. 



Skull and Lower Jaw, right 

 Ramus. This species is the most 

 gigantic member of the order of Ro- 

 dents hitherto discovered, whether 

 recent or fossil. It is akin to the 

 Beaver, but differs chiefly in a less 

 development of the cerebrum, in more 

 prominent though more slender, zygo- 

 matic arches, and in its dentition. The 

 incisors are fluted, and the molars 

 (numbering four in each ramus) con- 

 sist of a series of elongated elliptical plates of enamel which include the dentine. 

 The plates are directed obliquely across the crown. The C. differs from all other 

 Rodents in the size and conformation of the pterygoid processes and fossae. All 

 the processes and fossa? of the lower jaw are remarkably developed. The origi- 

 nal specimen, supposed to belong to an animal nearly six feet in length, was found 

 in 1841, in the Montezuma Marsh, near Clyde, N. Y., with shells of exist- 

 ing species, and is preserved in the Cabinet of Geneva College, N. Y. 



Size, 10x7. Price, $4.00. 



No. 22. Castoroides Ohioensis, Foster. 

 Lower Jaw, right ramus. 



Size, 8x4. Price, $1.50. 



Order 5 — Edentata. 



The Edentates include two genera (Myrmecophaga and Manis) which 

 are devoid of teeth ; the rest (with one rare exception) have molars 

 simply, which have no true enamel, are never displaced by a second 

 series, and are rarely implanted in the premaxillary bones. The Order 

 is limited in the number of species (forming only Jjth of living Mam- 



