ARTICLE n. 



ON THE INTEUCEXTlll'M OF THK TEUUESTKIAL VERTK13KATA. 



UY E. D. COPE. 

 Read before the American Philosophical Society, January i, 1886. 



Since the discovery of the rhachitomous Batrachiu, two difteroiit views of the 

 homologies of the segments which compose the l)odies of thrii- vertehne have Ijceii 

 maintained. According to the one first proposed, that of the writer,'" the segments in 

 the accompanying cuts of Trimerorhachis ins/'gnis Cope, and Eryops vmiacephalus Copi', 

 marked />, represent the centrum proper; while those marked /, are pieces which are 



ik^i^W^ {J 



Fig. 1. — Trimerorhnehh iriKif/nui ; a, occiput from behind ; 6, angle of the niaiidible, side ; r, do. from lieliind ; 

 (I, pnrt of vertebrnl column, lateral view, neural arclics resting on inlercentra through a loss of chorda dorsalis and 

 pressure ; e, do. obliquely from above ; », intcrcentra ; p, pleuroccntra. Original ; from Americau NaluralisI, 1884, p. 

 33. From the Permian of Texas. Natural size. 



intercalated hetween the true vertebra), and arc, therefore, appropriately termed {7iter- 

 centra. According to the second interpretation, that of Profi's.sor Gaudry,t the three 

 elements J5^^ and i, together, constitute a vertebra. It follows that /' cannol then be 



•American Naturalist, 1878, p. 337. Proceedings Amer. Philosoph. Society, 1878, p. ."ilO, 51.S, 532. Natumllsi, 

 1878, p. 633 ; 1886, 7.5. 



t Bulletin de la SociStu Geologitpie, France, 1878, p. 03; Enchaincmcnts du Monde Animal, 1883, p. 371. 



A. P. S. — VOL. XVI. 2e. 



