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Show 148 LAWS OF VARIATION. [0HAP. V. Poole who exatnined the breed for the. Indian Government 'a horse without stripes is not constdered as purelybred.' The spine is always striped; th~ legs. are geue:ally barred; and the shoulder-st::ipe, whwl~ IS ~ometlmes double and sometilnes treble, IS co_mmon, the SI~e of the face moreover is sometimes stnped. The ~tripes a~·e lai~est in th~ foal ; and somethnes quite disappear In ~ld horses. Colonel Poole has seen both gray and bay Kattywar horses striped when first f~aled. I have, also, reason to suspect, from informati?n given me by Mr .. w. W. Edwards, that with the Enghsh race:horse the spinal stripe is much commoner in the foal than In the f~1ll-grown animal. Without here entering on further details, I Inay state that I have collected cases of leg and. shoulder stripes in horses of very differen~ breeds, in vanous cou~tries fr01n Britain to Eastern Clnna ; and from Norway In the north to the Malay Archipelago in the south .. In all parts of the world these stripes occur far oftenest 111 duns and mouse-duns ; by the tern1 dun a large range of colour is included, from one between brown and black to a close approach to crea1n-colour. I am aware that Colonel I-Ia1nilton Smith, who has written on this subject believes that the several breeds of the horse have descend~d from several aboriginal speciesone of which, the dun, was striped ; and. that the aboyedescribed appearances are all due to anCient crosses With the dun stock. But I am not at all satisfied vvith this theory and should be loth to apply it to breeds so distinct as the 'heavy Belgian cart-horse, Welch ponies, cobs, the lanky Kattywar race, &c., inhabiting the 1nost distant parts of the world. Now let us turn to the effects of crossing the several species of the horse-genus. Rollin ~sserts,. that the common mule from the ass and horse 1s particularly apt to have bars on its legs. I once saw a mule with its legs so much striped that any one at first would have thought that it must have been the product of a zebra ; and Mr. W. C. Martin, in his excellent treatise on the horse, has given a figure of a similar mule. In four coloured drawings, which I have seen, of hybrids between the' ass and CHAP, V.] LAWS OF VARIATION. 149 zebra, the legs were much more plainly barred than the rest of the b.ody; and in one of them there was a double shoulder-stripe. In Lord Moreton's famous hybrid from a chestnut mar.e and male quagga, the hybrid, and even the pure offspnng subsequently produced from the mare by a black Arabian sire, were much more plainly barred ac~·o~s the legs than is even the pure quagga. Lastly, and this IS another most remarkable case, a hybrid has been :fi$ured by Dr. Gray (and he informs me that he knows of a second case) from the ass and the hemionus · and this hybrid, ~hough the ass seldom has stripes on it; legs and the hemionus has none and has not even a shoulder-stripe, nevertheless. had ~11 four legs barred, and had three short shoulder-stripes, hke ti1ose ~n the dun Welch pony, and ev?n had son1e zebra-hke stnpes on the sides of its face. With respect to this last fact, I was so convinced that not even a stripe of colour appears fr01n ·what would commonly be called an accident, that I was led solely from the occurrence of the face-stripes on this hybrjd from the ass and hemionus, to ask Colonel Poole whether such facestripes ever occur in the en1inently striped J{attywar breed of horses, and \Vas, as we have seen answered in the affirmative. ' What now are we to say to these several facts? We see several very distinct species of the horse-o-enus becoming, ~y simple variation, striped on the legsblike a zebra, or stl'lped on the shoulders like an ass. In the horse we s~e this. tendency strong whenever a dun tint appears-a tint which app.roaches to that of the general colouring of th~ oth~r speCies of th? s-enus. The appearance of the stnpes Is not accompanied by any change of form or by any other new character. We see this tendency to become striped most strongly displayed in hybrids from between several of the Inost distinct species. Now observe the case of the .severa~ breeds of pjgeons: they are descended from a p1geon (1ncludno- two or three sub-species • - b ' or geographical races) of a bluish colour, with certain ~ars and other marks; and when any breed assumes by ~1mpl.e variation a bluish tint, these bars and other marks Invariably reappear; but withd'tlt any other change of |