4 CATALOC4UE OF UNGULATES 



There is no alisphenoid canal traversing the bones of the 

 base of the skull ; and on the upper surface of the latter 

 there is no marked expansion of the upper extremities of 

 the nasal bones. As a rule, the premolar teeth are simpler 

 in structure than the molars, generally consisting, in the 

 case of those of the upper jaw, of a single lobe, instead of 

 two lobes ; with very few exceptions, the last lower molar, 

 and likewise the corresponding tooth of the milk-series, 

 consists of three lobes, whereas the others have but two 

 lobes. The femur lacks a third trochanter. The stomach 

 is nearly always more or less complex; and the caecum 

 relatively small. The placenta is diffused or cotyledonary ; 

 and the teats are inguinal or abdominal. 



FIG. 2. INNER ASPECT OF A SLIGHTLY WORN LEFT UPPER MOLAR TOOTH 

 OF THE NILGAI (Boselaphus tragocamelus) , to illustrate the tall- 

 crowned selenodont type. The accessory column is the slender 

 cylindrical one between the two crescentic inner main columns. 

 Nat. size. 



The existing representatives of the suborder are divisible 

 into the following sections and families : 



A. Upper incisors wanting. Ruminating. 



a. Horns or antlers generally present, at least in 

 males ; metacarpal and metatarsal 

 bones of main pair of toes fused, respec- 

 tively, into a single cannon-bone, termin- 

 ating inferiorly in a pair of pulley-like 

 condyles ; metacarpals and metatarsals 

 of lateral toes incomplete or wanting 



(fig. 1 B) ; stomach 4-charnbered PECORA. 



a ,'. Cranial appendages in the form of non- 

 deciduous unbranched horny sheaths, 

 supported on bony cores. Grown of 

 lower canine simple (fig. 4 A). World- 

 wide, except South America BOVID^E. 



