THE ARTIODACTYL UNGULATES 209 



which has progressed along lines of its own. Note the brachyo- 

 dont molars and the enormous size of the upper canines which 

 are especially tusk-like in the male though present in both 

 sexes. The elongation in the male may be associated with ab- 

 sence of horns. The chief diet of the animal consists of young 

 twigs and buds in the birch forests of the Himalayas above the 

 zone of pines. 



Of hollow-horned Ruminants, though the number of species 

 is very extensive, space will permit us only one example, 

 namely, the domestic Cow, Bos taurus (Fig. 76). The skull 

 illustrated is that of a young animal between two and three 

 years of age. The dental formula of the Cow like that of all 

 Pecora is: 



l|, Cy,P§,M§. total 32. 



In the specimen figured the milk canines and the prede- 

 cessors of the upper and lower third premolars together with 

 that of the second left upper premolar are still in situ. In gen- 

 eral the dentitions of the Cow and of the Sheep are very 

 much alike but in the former the incisors are less firmly im- 

 bedded and the cheek teeth have a well marked accessory style 

 not present in the latter. Most of the remarks already made 

 regarding the dentition of the Deer may be applied with equal 

 justice to that of the Cow. Regarding the absence of upper 

 incisors and canines it may be mentioned that embryological 

 investigation shoAvs that in the Cow as in the Deer the upper 

 canines were the last teeth to be lost. The valleys between 

 the cusps on the crowns of the bovine cheek teeth have a 

 greater amount of cement than those of the Deer. The last 

 lower molar presents a well marked extra cusp on the talonid. 

 The style present in the deep furrow notching the palatal 

 aspect of the upper molars shows very well the pronounced 

 amount of wear in these hypsodont teeth. In the specimen fig- 

 ured the style on the first molar, which erupted long before 

 the others, is alreadv considerablv worn. In the second molar 



