TAPINOCEPHALIDJS. 95 



obliquity of the zygapophyses at once distinguishes these 

 specimens from Pariasaurus. 



Presented by A. G. Bain, Esq., 1853. 



47106 a. The greater portion of a rib, associated with the preceding. 



Presented by A. G. Bain, Esq., 1853. 



The following specimen not improbably belongs to this group. 

 R. 1663. The imperfect right quadrate of a very large form ; from the 

 {Fig.) Karoo system of the Cape Colony. Figured by Seeley in 

 the ' Phil. Trans.' for 1889, pi. x. figs. 4-6, without generic 

 determination. This specimen differs from the quadrate 

 of the Dicynodontia by the presence of an antero-posterior 

 perforation above the trochlea ; and since there are no 

 other forms which are sufficiently large to have had a 

 quadrate of the size. of this specimen, there is a strong 

 presumption that it belongs to the present group. 



No history. 



Family Uncertain. 



The incisive teeth of the type referred to Deuterosaurus present 

 a remarkable approximation to the teeth of the American family 

 Bolosauridoe 1 , in which both the anterior and the cheek-teeth have 

 their crowns elongated at right angles to the axis of the jaw. The 

 American forms 2 do not have the dental series differentiated into 

 distinct tusks and cheek-teeth, and the dentition is regarded as 

 indicating herbivorous habits. The presence of a distinct tusk in 

 Biadectes and its absence in Empedias show, however, that such 

 differences are of no great importance. "Whether the cheek-teeth of 

 the skull referred to Deuterosaurus were transversely elongated is 

 not apparent. 



The humerus of the undermentioned forms approximates to the 

 type of that of the Tapinocephalidai, although of smaller size. The 

 vertebrae of Beuterosaurus and of the undermentioned African form 

 have a notochordal canal and the centra in the dorsal region much 



1 See Cope, ' Trans. Amer. Phil. Soc' vol. xvi. p. 288 (1886). In a com- 

 munication regarding the relations of these European forms to the Bolosaur idee 

 Prof. Cope writes to the author as follows : — " Your figure of the incisor re- 

 ferred to Deuterosaurus resembles a good deal the cheek-teeth of Bohsatcrus, 

 and less nearly the incisors of Empedias, owing to the weaker basal shoulder in the 

 latter. In the few known teeth of Chilonyx the basal shoulder is represented 

 by an angle only." 



2 In Chilonyx the temporal fossa) are roofed. See Cope, ' Proc. Amer. PhiJ. 

 Soc' vol. xx. p. 631. 



