142 EVOLUTION AND DISEASE. 
frequent on the outer side of the eye near the junction 
of the cornea and sclerotic. 
Similar hairy patches have been recorded as occurring 
on the conjunctive of dogs, oxen, and sheep ; in the 
latter animals these abnormal pieces of skin are fur- 
nished with wool. The specimen sketched in fig. 78 
represents a large patch of skin growing on the con- 
Fic. 78.—The cornea of an Ox with a patch of piliferous skin 
growing from it. (After Partridge.) 
junctiva of an ox. Some of these patches of skin 
have been examined microscopically and found to 
contain parts which are characteristic of skin in other 
situations of the body such as pigment, sebaceous, 
and sweat-glands. The developmental details of the 
conjunctiva indicate most conclusively that it is a 
modified piece of skin, and though in the individual 
