ISSO ] '^^ ' [Allen. 



Tiie vomer in the camel and llama advances far into the nasal chamber 

 before joining the bones at the floor of the nose. The choanae are there- 

 fore imperfectly defined. This peculiarity, however, is of little value, 

 since many forms of Cervus and its allies exhibit it. 



The squamosa! foramina are variable in different examples of the prong- 

 horn skull, but on the whole they may be said to resemble those of the 

 camel and the llama rather tlian those of other ruminants. 



The angle of the lower jaw is not trenchant but inconspicuous and 

 rounded in the three animals last named, and in this respect differs from 

 other ungulates examined. In place of the process on the posterior bor- 

 der of the ascending ramus, seen in the camel and the llama, the prong- 

 horn has the outline interrupted by an obscurely elevated rugosity. 



It must be conceded that the above resemblances between the prong- 

 horn and the family of the camels are decided, and it remains to point out 

 their significance. 



The Tylopoda and Pecora are separated by characters too profound to 

 be bridged by any of those enumerated, and in the absence of proof pre- 

 sented by paliEontology that the groups are connected through the me- 

 dium of one or more extinct forms, it must be concluded that the charac- 

 ters are adaptive on the part of the pronghorn to enable it to live on 

 terms of the same kind that environ the camel and the llama. 



