458 MAMMALIA. 



the horse in that the ribs are broader, longer, and flatter, and 

 there are thirteen on each side ; the sternum is flat and not keel- 

 shaped ; the scapula is broader at the top, and the premaxillary 

 bones do not carry teeth. The frontal bones of the skull are 

 enormously developed (fig, 217). The upper part of the frontal 

 bone forms the pole. The pole is thick, owing to the sinus in 

 the frontal bones, and bears laterally the conical bony cores that 

 support the horns. The ox, sheep, and goat have a third tur- 

 binated bone in the nasal cavities. In the foot of the ox and 

 sheep the cannon-bone is composed of the fused third and fourth 

 metacarpals and metatarsals ; each digit is free, and carries a 

 hoof. A rudimentary third metacarpal is seen in the ox. The 

 ulna, as in the sheep, extends the whole length of the radius. 

 The kidney of the ox is lobulated. The sexual organs of the 

 Bull have certain peculiarities : there are no Cowper's glands, 

 the penis is long and thin, and lies in an S-shaped curve when 

 retracted. Most of the wild species are capable of domestica- 

 tion. The parent stock of our various breeds of cattle is not 

 known for certain. Some suppose that the beautiful white 

 Chillingham cattle, once wild over England, and now only pre- 

 served in one or two places, are descendants of the wild cattle 

 of Europe, the Urus or mountain bull (Bos primigemus), which 

 existed in numbers in a wild state in Gaul at the time of 

 CcEsar's invasion. The three most important races of oxen 

 which have been traced back to B. iwiiingenius are — 

 (i) The Bracbyceros race (Appenzell cattle), 

 (ii) Primigenius race (Holland cattle), 

 (iii) Frontosus race (Bern cattle). 

 Another wild Bovis in Europe was the so-called British Short- 

 horn {Bos longifrons), now extinct. Very probably most of our 

 smaller short-horned varieties are descended from this wild 

 species. Another wild species in Britain was the Auroch (Bos 

 bison), a large species, which still exists in a wilil state in the 

 Caucasian forests. 



