43 1 - 



follow Mendelian laws, it should be possible to produce a sheep 

 having the white face of the Dorset combined with the absence of 

 horns characteristic of the Suffolk, and, moreover, one which will 

 breed true to this novel combination. Further, the desired result 

 should be attainable by breeding two generations only. And so it 

 proved ; for, by breeding together the first crosses between Dorsets 

 and SufTolks, there was obtained a ram having all the points of 

 the Suffolk except that, instead of having a black, it had a white 

 face. It is clear, therefore that the something, whatever it may be, 

 that causes the blackness of the Suffolk is inherited independently 

 of the other characters, and can be replaced by the something 

 which produces whiteness, just as we can pick out one piece of a 

 mosaic and replace it by one of another colour without disturbing 

 the remainder of the picture. The method adopted to secure this 

 rearrangement of the mosaic is simply to interbreed the first crosses 

 between individuals containing the pieces we want, knowing that 

 the offspring of the union, if sufficiently numerous, will include the 

 new combination we are in search of. 



R. I. POCOCK. On the colours of Horses, Zebras and Tapirs. 



(Ann. and Mag. Nat. Hist. (London) 8, ser., 4 (1909), no. 23, 

 pp. 404, 415). E. S. R. March, 1910 Washington. 



This contains a discussion of the nomenclature of colors and 

 color patterns in Equidae and other large mammals. Various theo- 

 ries which account for the causation and inheritance of albinism, 

 dappling, and the zebroid pattern are reviewed. The author thinks 

 that the Equidae are descended from dark colored animals patterned 

 with white spots, running into longitudinal lines originally and in 

 a late state of evolution becoming arranged in transverse bars over 

 the neck and body. If this theory is true, then the white spots 

 of dapple-grey horses represent phylogenetically the white spots of 

 a tapiroid progenitor, a stage antecedent to the vertical zebroid 

 bands hitherto regarded as the most primitive pattern extant in the 

 Equidae. 



J. C. EWART. The possible Ancestors of the Horses living 

 under domestication. (Science, n. ser. 30 (1909), No. 763, 

 219-223; Proc. Roy. Soc., ser. B, 81 (1909), No. 6549,392-397); 

 abs. E. S. R., XXI, Dec. 1909. 



These are abstracts of a paper presented before the Royal Society, 

 London. 



