Experimental Contributions to the Theory of Heredity. ' 247 



As to the occurrence of stripes in other breeds I could give, were it 

 necessary, many instances. A year ago I had in my possession a light 

 bay (or yellow dun) pony, which showed nearly as many stripes on 

 the trunk as the Gore-Ouseley filly, and in addition had several in- 

 terrupted narrow stripes on the forehead.* Moreover, the stripes on 

 the Gore-Ouseley " colts," while agreeing with stripes occasionally seen 

 in horses, differ in their arrangement from the stripes in the quagga.. 

 The stripes themselves are evidence of reversion, but nothing more, 

 and seeing that pure bred horses sometimes show quite as many stripes, 

 we are not justified in assuming that but for the dam of the " colts "' 

 having been first mated with a quagga the stripes would not have 

 appeared. 



Hence unless it is proved that the mane in the filly and colt were 

 naturally erect, or nearly erect, the case for the " infection " of Lord 

 Morton's mare will be lost. It may be well to quote the passage from 

 Lord Morton's letter referring to the mane. It is as follows : — " That 

 of the filly is short, stiff, and upright, and Sir Gore Ouseley's stud 

 groom alleged it never was otherwise. That of the colt is long, but so 

 stiff as to arch upwards and to hang clear of the neck, in which circum- 

 stance it resembles that of the hybrid. This is the more remarkable 

 as the manes of the Arabian breed hang lank and closer to the neck 

 than that of most others."! 



I am not prepared to accept the allegation as to the manes for the- 

 following reasons : — 



1. I have had twelve zebra hybrids under observation, and in 

 each case the mane, though erect to start with, always after a time 

 arched over to one or both sides. The stud groom's statement, it 

 seems to me, proves too much. If in the quagga hybrid and in all 

 my horse hybrids the mane, sooner or later, falls to one side, it is 

 a little remarkable that in the pure bred two-year-olcl filly it had been 

 always upright. 



I may here mention that the hair of the mane of zebra hybrids is 

 shed annually ; it is for this reason that the mane in hybrids is never 

 long enough to hang close to the neck. 



2. The mane in the drawing of the filly by Agasse is not represented 

 as upright, but as lying to one side. If the mane had remained erect 

 during the first two years, by virtue of shedding its hairs, it could not 

 very well have lost this habit and fallen completely over to one side 

 subsequently, say, during the fourth year. From the mane being erect 

 in 1820, and hanging to one side in 1821 or 1822, when Agasse's 

 drawing was made, the presumption is that the mane of the " colts " 

 had been cut some time before they were examined by Lord Morton. 



Two years ago I had a bay Arab with a mane which was to start 



* See Fig. 36, ' The Penycuik Experiments,' A. and C. Black, 1899. 

 f < Phil. Trans.,' 1821. 



