Cope.] 1'^-' [Dec. 16, 



base. The external and posterior internal arc of about the same size ; 

 the anterior inner is smaller and does not project so far inwards as the 

 posterior. The fourth premolar has the posterior border of its heel ser- 

 rate. The anterior cusps are elevated and moderately acute ; the internal 

 is a little less elevated than the external, and is separated from it by a 

 deep notch. The alveoli for the anterior premotar are so close together, 

 as to render it probable that they belong to but one tooth. They are 

 placed somewhat obliquely to the long axis of the jaw. There is no 

 diastema. The section of the base of the crown of the canine is a regular 

 oval, the long diameter coinciding with the vertical diameter of the 

 ramus. 



The ramus is rather slender, but is shortened anteriorly. The bound- 

 aries of the masseteric fossa are well marked, the anterior ridge descend- 

 ing to below the middle line of the ramus. The mental foramen is large 

 and is situated below the contact of the two premolars. The inferior edge 

 of the ramus is rather thick. 



Measurements. M. 



Length of dental series including canine 0240 



' ' premolars 0063 



" molars 0114 



Long diameter base canine 0036 



^. ^ ^^^ ( anteroposterior 0038 



D ameters P-m. IV T ^^,„ 



i| transverse 0026 



, ^, (anteroposterior 0042 



" M. IL K AAOO 



i transverse 0038 



Depth of ramus at P-m. 1 0060 



" M. Ill 0068 



Anaptomorphus homuncultjs Cope, American Naturalist, 1882, Jan. 

 (Dec. 30th, 1881), p. 73. 



The genus Anaptomorphus was characterized by me in 1872,* from a 

 mandibular ramus which exhibited the alveoli of all the teeth, three of 

 them occupied hy the teeth ;- viz. : the P-m. iv, and the M. i and M. ii. 

 From the specimen the inferior dental formula was ascertained to be I. 2 ;' 

 C. 1 ; P-m. 2 ; M. 3. The Big-Horn collection contains a nearly entire 

 cranium of what is probably a species of the same genus. From it the 

 superior dentition, exclusive of the incisors, is determined to be : C. 1 ; 

 P-m. 2 ; M. 3. The premaxillary bones are mostly broken off, but a part 

 of the alveolus of the external incisor of one side remains. 



The indications are that the external incisor was a small tooth, not 

 exceeding the canine in size ; and it was situated close to the latter. The 

 canine is also small, and its simple crown is not more prominent than those 

 of the premolars. The latter are separated from it b}'^ a very short diastema. 

 The long diameter of their crowns is transverse to the long axis of the 



» Proceedings American Philosophical Society, 1872, p. 551. Paleoutological 

 Bulletin, No. 8, p. 1, Oct. 12, 1872. 



