180 Mr. W. Heape. On the Transplantation and Growth of 



young ; in a third she gave birth to eleven Belgian Hare young ; 

 while in the fourth case the Belgian Hare doe gave birth to seven 

 young, of which, five were Belgian Hares and two were apparently 

 Dutch. 



When the young began to run about, I observed that both these 

 Dutch young were irregularly marked, and at first I was inclined to 

 think it was possible, after all, either — 



(1) That the Belgian Hare foster-mother had influenced the Dutch. 



fertilised ova ; or 



(2) That these two young were really a cross between Dutch and 



Belgian Hare. 



In order to test the first of these possibilities, I made the following 

 experiment. I put the same Dutch buck which had been used in the 

 foregoing experiment, to a thorough-bred Dutch doe, and she pro- 

 duced a litter every one of which was badly marked, most if not all 

 of them, were as badly marked as the Dutch foster-children, while 

 certain of them were even worse marked. 



This Dutch doe I bred myself ; she was one of an exceptionally good 

 litter, and I obtained out of her by another buck, the previous year, a 

 very good litter. I have no doubt the bad marking of the young in this 

 last litter is the fault of the buck now beingused ; he is not well bred. 

 Dutch rabbits frequently have some badly marked young in their 

 litters, even when they are themselves excellently well-bred animals, 

 but the litter described above consists altogether of outrageously 

 badly marked young ; in fact most of them could not be recognised 

 as Dutch at all, as far as their marking is concerned. 



This experiment therefore shows that the bad marking of the foster- 

 children can be fully accounted for by the fact that their father is 

 badly bred, and it is not necessary therefore to suppose that the 

 foster-mother is the cause of the irregularity. 



The second possibility is, however, far more difficult to test, and I 

 do not hold that, under the circumstances attending my experiment, 

 it is possible to determine it quite satisfactorily ; at the same time I 

 think a strong case of probability can be made out. 



With regard to the possibility of getting a cross between the 

 Dutch buck and the Belgian Hare foster-mother, in consequence of 

 my experiment, it is by no means impossible this should have been 

 done ; for it must be remembered that when the foreign Dutch seg- 

 menting ova were introduced into the fallopian tube of the Belgian 

 Hare foster-mother, they were still surrounded by spermatozoa from 

 the Dutch buck, spermatozoa that Ave re still alive though perhaps 

 failing in vigour; and numbers of these Dutch spermatozoa, there 

 can be little doubt, were introduced into the foster-mother's fallo- 

 pian tube along with the Dutch fertilised ova. 



