70 



Annals of the Carnegie Museum. 



the apex slightly recurved. P- is single-rooted as in Homacodon 

 and has a trenchant crown. P- has a considerably greater fore- and- 

 aft diameter, but is otherwise quite similar to the preceding tooth. 

 P- differs from that in Homacodon by the presence of an internal 



Fig. 10. Hylotneryx annectetjs. Carnegie Museum No. 2944. X i 1/2. 



tubercle situated well back, which may be regarded as the deutero- 

 conid. P- is entirely different from that tooth in Homacodon and 

 more nearly suggests that in Bunomeryx. Thus the deuteroconid is 

 prominent,^" there is a decided antero-internal tubercle and a heel 

 differing both from Professor Marsh's illustration {Amer. Jour. Sci., 

 Vol. XLVTII, 1894, p. 262, Fig. 6), and Sinclair's description {I.e., 

 p. 284). Marsh has stated that this tooth in Homacodon vagans has a 

 simple crown, while Sinclair, without criticizing Marsh, says that there 

 is no deuteroconid, but a prominent anterior tubercle and almost as 

 prominent a posterior basal tubercle rising from a cingulum-like heel. 

 The lower molars are of a type further advanced toward the seleno- 

 dont structure than those of Homacodon. 



M EASUREMENTS. 



Type Paratype 

 No. 2335. No. 2926. 

 Antero-posterior diameter of skull from anterior border of 



orbit to canine 32 mm. 



Length of cheek dentition 39 " 38 mm. 



Length of superior premolar series 22 



Length of superior molar series 16 " 



Antero-posterior diameter of P- 3 " 



^ In the type, which pertains to a younger individual than the paratype, the 

 deuterocone and antero-internal tubercle are less prominent; less distinctly separ- 

 ated from the protoconid, and situated higher up on the crown. 



