Experimental Contributions to the Theory of Heredity. 249 



Arthur Cecil. The better bred West Highland ponies are supposed to 

 have descended from " Armada " horses, and are hence perhaps related 

 to Mexican and Argentine horses, so often dun-coloured and partially 

 striped. Mulatto's hybrid (Eomulus, born 12th August, 1896) is on 

 the whole more a zebra than a pony both mentally and physically. 

 He is especially remarkable in being more profusely striped than his 

 sire (the zebra Matopo), in having a heavy semi-erect mane, which is 

 shed annually, and in having a mule-like tail, from the upper third of 

 which the longer hairs are periodically shed. The body colour of the 

 hybrid varies from a dark orange colour to a mouse dun ; the stripes 

 of a reddish-browD colour on the head are dark brown or nearly black 

 on the trunk and limbs. 



In the number and plan of the stripes, the hybrid agrees more 

 closely with the Somali zebra than with any of the Burchell zebras. 

 Over the brow, e.g., there are narrow rounded arches instead of some- 

 what broad pointed arches as in his sire, the neck and trunk have 

 quite double the number of stripes found in the sire, while over the 

 croup in the position of the " gridiron " of the mountain zebra there 

 were at birth irregular rows of spots which in course of time blended 

 to form somewhat zig-zag, narrow, transverse bands. The ears are 

 nearly as large as in the sire, while the eye-lashes are longer and dis- 

 tinctly curved. In his movements the hybrid resembles his sire, and 

 like his sire he is always on the alert, very active and suspicious of 

 unfamilar objects. Further in his call he agrees far more with his sire 

 than his dam. In being profusely striped, Romulus differs greatly 

 from the quagga hybrid bred by Lord Morton, in which the stripes 

 were fewer in number than in many dun-coloured horses. 



Mulatto's second foal arrived in July, 1897, the sire, Benazrek, 

 being a high-caste grey Arab horse. Like Lord Morton's colts, 

 Mulatto's foal by the Arab horse, in make, action, and temperament, 

 agreed with ordinary foals, but it differed from the majority of 

 foals in presenting quite a number of indistinct stripes — subtle mark- 

 ings only visible in certain lights. These stripes differed but little 

 from the body colour, which varied from dark bay to brown. Though 

 few references have been made to the occurrence of stripes in foals, 

 they are, we find, far from uncommon. As is well known, Mr. 

 Darwin once bred a striped foal by putting a cross-bred bay mare to 

 a thoroughbred horse. This foal was for a time marked nearly all 

 over with obscure dark narrow stripes, plainest on the forehead, but 

 also distinct over the croup.* 



There is no figure of Mr. Darwin's striped foal, but from the descrip- 

 tion given, there can be little doubt that the markings were more 

 abundant than in Mulatto's second foal. In this foal (as in Mr. Dar- 

 win's) the stripes became more and more indistinct, and by November 

 * ' Animals and Plants,' to! . 1, p. 60. 



