Cope.] J--'* [May 15. 



and their loss would bring us again to the Testudinata type. Their 

 implantation in deep alveoli is reptilian in character. 



I have pointed out that the notch in the posterior border of the cranial 

 table in the stegocephalous Batrachia was probably covered by a mem- 

 branum tympani, since the stapes terminates there. This notch is the 

 first appearance of a meatus auditorius in the Vertebrata, and it is not 

 present in all Stegocephalia. It seems that the members of the Cotylo- 

 sauria differ among themselves similarly, some presenting the meatus, 

 and others lacking it. In Conodectes the character approaches tliat of 

 the Stegocephalia more nearly than it does in OtocQ?lus. 



In tlie American Naturalist for 1885, p. 247, I publislied the conclu- 

 sion that the Testudinata were descended from the Theromora. In my 

 system at that time the Theromora included the Cotylosauria. In 1892 

 {Trans. Amer. Philos. Soc, p. 24), I distinguished the Cotylosauria as 

 the primitive source of the Testudinata. The discovery of the Otocffilidse 

 renders it almost certain that this anticipation was correct. 



In this family the slight posterior concavity of the quadrate region of 

 the Diadectidie is extended forwards to a great distance, and the osseous 

 tympanum is produced further outwards. The position of the parts is 

 difierent from that which is characteristic of the Stegocephalia, where 

 the tympanic notch, when present, is superior, owing to the much greater 

 length of the suspensorium. The dental characters also distinguish this 

 family from the Diadectidte. No ossicula auditus were found in the tym- 

 panic cavity. 



Two genera of this family are known, and are characterized as follows: 



Mandible articulated much anterior to cranial Ijorder; nostrils opening 

 vertically Otoco'lus Cope. 



Mandible articulated posteriorly and on line of posterior border of 

 skull ; nostrils opening horizontally Conodectes Cope. 



Two species of Otocoelus and one of Conodectes are known from the 

 Permian bed. 



Otoccelus testudineus, Amer. Naturalist, 1896, 399. 



Char. gen. — Teeth with simple subconic crowns. 3Iandibular ramus 

 not produced posterior to quadrate. Superior cranial bones strongly 

 sculptured. 



This genus is established on a skull from which the muzzle anterior 

 to the orbits has been broken off. On its under side, pushed forwards 

 out of place, are a considerable part of the shoulder-girdle, the head of 

 the humerus and a bone of the forearm. On anotlier block, which was 

 found with it, is a part of the carapace, two vertebr;v, numerous ribs 

 and both hind legs, lacking the tarsus and digits. The legs and vertebne 

 were not found attached to the foreleg and the skull, but the actual con- 

 tact of the corresponding parts is found in the type specimen of another 

 species, tlie 0. iniineticus. 



