PHYSICAL CHARACTERS IN MAN 99 



In crosses they sliowed alternative inheritance, but 

 they tinally became extinct. Another pair of solid- 

 hoofed pigs was received by the Zoological vSociety 

 of London from Cuba in 1876. Auld (1889) reports 

 sohped (solid-hoofed) swine from Texas in 1878. They 

 bred true, and when crossed with the normal gave a 

 majority of solipeds. Another breed of solid-hoofed 

 hogs was reported from a farm at Sioux City, Iowa, 

 and a wild herd from near Baton Rouge, Louisiana. 

 In another instance a Poland-China boar with one 

 solid hoof had many offspring in the same condition. 

 Probably the solid-hoofed condition has arisen many 

 times through independent mutations. 



A peculiar case is recorded by Colonel Hallam* of 

 a race of pigs observed in a town on the coast of the 

 Tanjore countr}' in 1795. Drawings of two in- 

 dividuals were submitted. The pigs had only two 

 legs, the hinder extremities being entirely wanting. 

 They bred true for at least three generations. Such 

 cases must arise through some mishap to an element 

 of the germ plasm. 



Darwinf cites the following conditions in horses 

 as plainly hereditary: ring-bones, curbs, splints, 

 spavins, founder and weakness of the front legs, 

 roaring or broken and thick wind, melanosis, specific 

 ophthalmia, blindness, crib-biting, jibbing, and ill- 

 temper. He quotes Youatt : " There is scarcely a 

 malady to which the horse is subject which is not 

 hereditary." 



Many records of syndactyly in man are extant, 

 but usually the inheritance has only been traced from 

 parent to offspring. It is recognised as a Mendelian 

 dominant condition. Hurlin (1921) describes a case 

 of limited syndactyl}^ in an old New England family 

 in which the web occurs only between the second and 



* Proc. Zool. Soc, 1833, Part I., p. t6. 

 t Animals and Plants, chap, xii., p. -45^. 



