1 42 E VOL UTION 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- 



FIG. 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 



