340 A MEMOIR ON THE EXTIiN'CT 



last molar tooth of Protochoerus and the cave head may be variable in the same species; 

 but of this we must remain in doubt until further discovery of more material: and until 

 further evidence can be brought to prove the cave head belonged to Protochoerus it will 

 be at least of advantage in the way of reference to consider the former as distinct, and I 

 therefore propose for the animal to which it belonged the name of Euchccrus macrops. 



In conclusion, in answer to what may be urged by some naturalists, that the characters 

 given of Platygonus, Protochoerus, and Euchcerus are not sufficient to rank them as dis- 

 tinct genera from Dicotyles, I must add that it will be admitted that the recognised species of 

 the latter present characters in common not possessed by any of the preceding genera, and 

 therefore these should be distinct, and among these new genera differences exist, quite as 

 important as those separating them from Dicotyles. Those who acknowledge the distinc- 

 tion between Machairodus and Felis, Ovibos and Bos, Acerotherium and Rhinoceros, etc., 

 will readily admit this reasoning, and with such naturalists who are so precise as to con- 

 sider Bison, Bubalus, Bibos, etc., distinct from Bos, or Alces, Tarandus, Cariacus, Mega- 

 aceros, and Strongyloceros, etc., from Cervus, the matter is beyond dispute. 



Comparative Admeasurement 's of the head of Dicotyles torquatus, I). labiulus, and Euchcerus macrops. 



D. torquatus. D. labiatus. E. macrops. 



Length of head from occipital condyle to incisive alveoli, 8 in. 3 lines. 9 in. 6 lines. 11 in. 3 lines. 



Distance from inion to end of nose, - - - -9" 10 " 3 " 



" " supra-orbit. foramina to end of nose, - 4 " 3 " 4 " 9 " 4 " 



Length of os frontis at middle, -----* 2"1" 



Greatest breadth of forehead, 3 " 3 " 5 " 4 " 5 " 



Breadth at anterior glenoid tubercles, - - - 4 " 4 " 9 " 4 " C " 



" infra-orbitar foramina, - - - - 1 " 4 " 1 " 10 " 1 " 



Length of face from ant-orbital margin to incisive alveoli, 5 " 4 " 6 " 3 " 8 " 6 " 



Breadth at canine alveoli, 2 " 6 " 2 " 7 " 2 " 5 " 



" lateral incisors, 1 " 2 " 1 " 3 " 1 " 4 " 



" ossa nasi at ends of intermaxillaiies, - 1 " 1 " 



Distance between supra-orbital foramina, - - - 1 " 1 " 11 " 1 " 5 " 



Height from midway between supraorbital foramina to level 



of palate, 2 " 10 " 3 " 6 " 3 " 6 " 



Height between canines, - - - - - - 1 " 9 " 1 " 9 " 2 " ? " 



Height of inion, 3 " 6 " 3 " 9 " 3 " 7 " 



Vertical diameter of orbit, 1 " 5 " 1 " 7 " 1 " 4| " 



Transverse " " 1 " 2 " 1 " ?i " 1 " 7 " 



Depth of os mala below orbit, 10 " 1 " 1 " 1 " 8 " 



" " from end of post-orbital process, - 1 " 2 " 1 " 5| " » 2 " 5 " 



From meatus audit, ext. to end of post-glenoid tubercle, 2 " 2 " 6 " 3 " 



Length of hard palate, 5 " 6 " 7 " 7 " 9 " 



Breadth between first true molars, - - - - 11 " II " II " 



Length of upper molar series, - - - - - 2 " 9 " 3 " 3 " 1 " 



Length of hiatus anterior to molars, - - - - 7 " 1 " 2 " 1 "10 " 



" " " to canines, .... 8 " 10 " 9 " 



* From obliteration of some of the sutures, I am not able to give all the measurements. 



