1916] 



Chandler: Notes on Capromeryx 



117 



in Capromeryx this is only suggested by a slight elongation of the 

 third lobe. It is interesting to note that in an abnormal specimen 

 of Antilocapra americana (U. C. M. V. Z. no. 8299) the last lobe is 

 missing, the condition being identical with that found in Capromeryx. 

 M 3 of the latter is directly intermediate between Antilocapra and the 

 older Merycoelus, since in the latter the third lobe is not only not 

 divided but is considerably smaller than either of the other lobes. 



The degree of hypsodonty of both milk and permanent teeth is 

 comparable with that in Antilocapra, being far in advance of Meryc- 

 oelus in this respect, as has previously been pointed out by Taylor for 

 the milk dentition. As is indicated below, the lower jaw is relatively 

 shorter than that of the pronghorn, and while the lower row of cheek- 

 teeth is longer in Capromeryx relative to the length of the jaw, it is 

 shorter relative to the size of the body, which in most measurements 

 averages about two-thirds the size of Antilocapra. 



The mandible of Capromeryx minor differs considerably from 

 Antilocapra in its proportions. The depth of the jaw is relatively 

 much greater in Capromeryx ; the vertical ramus stands more nearly 

 at right angles to the horizontal ramus ; the diastema between cheek- 

 teeth and incisors is almost equal to the length of the tooth-row in an 

 Antilocapra in which the permanent dentition is all functional but 

 slightly worn, while in a specimen of Capromeryx of similar age it 

 is less than two-thirds as great ; the anterior dental foramen is much 

 nearer the tip of the symphysis than to P 2 in Antilocapra, while in 

 Capromeryx it is about half-way between, on account of the shortening 

 of the jaw between the foramen and the cheek-teeth. To sum up, it 

 may be said that the jaw of the diminutive extinct antelope is rela- 

 tively shorter and heavier than that of its modern relative, and that 

 this shortness of the jaw very probably was correlated with a shorter 

 snout. 



VEBTEBEAE AND EIBS 



Axis. — The axis very much resembles that of Antilocapra, but has 

 a deeper and thinner ventral ridge, and a relatively smaller centrum. 

 The transverse processes do not reach as far posteriorly as the ventral 

 tip of the centrum, whereas in Antilocapra they reach very consider- 

 ably beyond. The vertebraterial canal is relatively very large. 



Thoracic vertebrae. — A fragment of what is probably the eighth 

 thoracic vertebra has been found. It has a relatively long centrum 

 and large demifacets for rib articulations. 



