J22 Hagedoorn. 



the colouring of the extremities, nose, feet, ears of albino young, at 

 the time of the first moult, these points differ in colour in corre- 

 spondance with the gametic formula of the animal, thus are there 

 rabbits with black, whites with agouti, and whites with chocolate 

 extremities. It is not yet sure whether the presence or absence of this 

 factor can be discerned in coloured rabbits, but the results I have 

 seen from crossing darknosed whites with chocolate would indicate 

 that this is not possible. Miss Sollas has found that the points of 

 a cavy without B or c are the lightest. Cavies with pure white noses 

 and ears, such as there exist rabbits and mice are unknown to the 

 fancy. I have seen a few cavies whose noses were absolutely white, 

 although the ears were coloured, and from the fact that in the same 

 collection of thousands (bred for the Pasteur Institute at Paris) there 

 were some which had a broad black nose with a white blaze in the 

 middle of it, I think it safe to assume that they lacked the factor L, and 

 would have been spotted with white if they had had a coat, coloured 

 through other factors. I would be perfectly possible to breed a strain 

 of white cavies with white noses and black ears, from coloured parents 

 patched with white, heterozygous in a. From the appearance of those 

 few cavies, in which the black spot on the nose, caused by presence 

 of N was broader than the white blaze caused by absence of L, I think 

 it may be assumed that factors N and L are independantly trans- 

 mitted. The independance of N and a can be shown by breeding 

 coloured rabbits throwing albinos, (Aann) to himalayans (aaNN), and 

 breeding two kinds of albinos in Fo, such with coloured points (aN) 

 and such with white points (an). This has been done by Captn. 

 Smits in Utrecht, Holland, to whom I am indebted for the data. 

 It is impossible to speculate as to how Mus miisadus stands in 

 relation to this factor, as mice with coloured points are not bred as 

 far as I know. One of the mice figured by Plate looks almost like 

 a himalayan rabbit, though the history of its colouring excludes the 

 possibility of its having the factor N. 



Factor 0. 

 This factor has been studied by Hurst. It is know only in the 

 rabbit, at least, it has only been studied in that animal. Its presence 

 makes an otherwisely black animal "Black and tan", that is, with 

 a coat, black, with the exception of those parts which in an agouti 

 animal are lightest, a spot behind the ear, rings around the eyes, 

 the throat, belly and legs, which parts are mostly yellow. Otherwisely 



