SUBORDER D ARTIODACTYLA 217 



Blumenbach occurs in the Pleistocene of India, and Bubalus Elitimeyer 

 (Fig. 294) in the Pleistocene of Europe and Algiers. 



B. Leptobos Group. 



Skull loiv, much elongated. Horns arising immediately behind the orbits, bases 

 widely separated, not very powerful, subcylindrical or but little flattened below, 

 directed backward, sometimes entirely absent. Parietal bones relatively large, 

 appearing on the upper surface of the skull. 



The single genus Leptobos Riitimeyer is found in the Pliocene and Pleis- 

 tocene of northern India. L. falconeri Eiitimeyer. According to Forsyth 

 Major, Bos etruscus Falconer from the Pliocene of Val d'Arno, Auvergne and 

 Spain, belongs to the genus Leptobos. Teeth from the Pliocene Bohnerz of 

 Melchingen may also pertain to this group. 



C. BiBOs Group. 



Posteriorly frontal bones strongly expanded transversely, frontal region much 

 expanded and flat ; parietal region distinct only in the young, later excluded from 

 the cranial roof. Horns more or less flattened, situated far back on the fronto- 

 occipital border ; in the young directed backward, in the adult laterally. 



Eecent and fossil representatives of the genus Bibos Hodgson are found 

 in southern India, and a Pleistocene species in Java. 



D. Bison Group. 



Skull low, frontal region flat, unusually broad and relatively short, the cylindrical 

 horns directed outward and upward, and standing a short distance behind the very 

 prominent orbits. Parietal bones short, broad, but always developed on .the cranial 

 roof. Facial portion of skull short. Nasal bones short, broad posteriorly. 



Two species of this group survive at the present day, the European aurochs, 

 B. europaeus Gmelin in Lithuania, and the American bison in North America. 



Bison priscus Bojanus sp. is found in abundance in the Pleistocene of 

 Europe and northern Asia. Pleistocene bison are also found in North 

 America, the species being known as B. antiquus Leidy and B. latifrons Harlan. 

 The fossil European aurochs is more closely allied specifically to the fossil 

 and existing American bison than to B. europaeus- The oldest remains of the 

 bison are found in the Upper Pliocene of northern India. B. sivalensis 

 Falconer. 



E. Taurus Group. Oxen. 



Frontal bones enormously expanded, forming the entire cranial roof ; parietal 

 bones unusually short and quite excluded from the cranial roof. Position of the 

 horn-cores removed far back to the postero-external angles of the skull. 



In this group the structure of the bovine skull has reached the culminating 

 point. The frontal region has gained an extraordinary expansion, and the 

 parietal zone has experienced a reduction seen in no other division of the 



