THE ANATOMY OF THE OX. 81 



The tapetum lucidum of the eye is of a golden green colour, 

 inclining to blue at the circumference. The " gland of Harder " 

 is present in all the domesticated animals. The eye of the 

 ruminant is in most respects similar to that of the solipede. 



The liair on the tail of the ox, as in the ass, is long only at 

 the end, where it forms a tuft. Between the horns, the hair is 

 thick and curly, but these qualities vary in degree with the 

 breed. The wool found on some of the smaller ruminants is a 

 kind of hair. 



The Jiorns consist of a layer of horn tissue which has been 

 developed by the vascular and nervous membrane which covers 

 the horn-core, forming at its base a circular pad, continuous with 

 the dermis. Both the membrane and the pad produce horn- 

 tissue, and hence the tissue of horns, in like manner with the 

 wall of a horse's hoof, is derived from two sources. The portion 

 of the horn surrounding the pad is known as the root^ that cover- 

 ing the core the body, while the part projecting beyond the core 

 is the 'point. The horn presents a number of rings just above 

 its root. Horns vary greatly in shape. In the bovidsB the 

 typical form is crescentic, the convexity being turned more or 

 less downwards and outwards. In the ovidse the horns are, as 

 a rule, curved spirally, and sometimes very gracefully curled, 

 the first bend being convex outwards and forwards. In the goat 

 they are closer together, and more perpendicular, being slightly- 

 curved with the convexity inwards. Camels are devoid of horns, 

 whereas other ruminants have horns of large size. Animals pos- 

 sessing horns of the above type are called cavicornia, or hollow- 

 horned animals. The horns of deer differ in being formed of 

 solid bone, in having branches, and in falling off every year, to 

 be replaced by new ones. The hoof is divided into two parts, 

 one for each digit, each part resembling in shape the distal 

 phalanx. Their general structure resembles that of the horse's 

 hoof, but the frog is little developed. A small horny projection 

 appears on each side of the posterior aspect of the fetlock. 

 These are rudimentary hoofs, each containing a small bone not 

 connected with the skeleton. 



