178 Mr. W. Heape. On the, Transplantation and Growth of 



of the paired bodies of Elasmobranchs with the medulla of the 

 mammalian suprarenal. The direct evidence in favour of the homo- 

 logy of the interrenal with the cortex of the suprarenal is mostly 

 morphological and histological, and I have detailed this elsewhere.* 



"Further Note on the Transplantation and Growth of Mam- 

 malian Ova within a Uterine Foster-mother." By Walter 

 Heape, M.A., Trinity College, Cambridge. Communicated 

 by Dr. W. H. Gaskell, F.K.S. Received November 2, — 

 "Read November 25, 1897. 



In 1890 I recordedf an experiment designed to show that it is 

 possible to make use of the uterus of one variety of rabbit as a 

 medium for the growth and complete foetal development of fertilised 

 ova of another variety of rabbit. 



The experiment was further undertaken in order to determine 

 what effect, if any, a uterine foster-mother would have upon her 

 foster-children, ana whether or not the presence, during development, 

 of foreign ova in the uterus of a mother would affect offspring of 

 that mother present in the uterus at the same time. In the experi- 

 ment above referred to, two fertilised ova were obtained from an 

 Angora doe rabbit which had been inseminated thirty-two hours 

 previously by an Angora buck, and they were inserted into the 

 fallopian tube of a Belgian Hare doe, which had been inseminated 

 three hours before by a Duck of the same breed as herself. 



In due course the Belgian Hare doe littered six young, four of 

 which were Belgian Hares, while the other two were Angoras. There 

 was no trace of any cross in any of these young, the four Belgian 

 Hares and the two Angoras were true bred. 



The experiment seemed to me to show, so far as a single experi- 

 ment could show, that a uterine foster-mother has no power of 

 modifying the breed of her foster-children, and that her uterus 

 during gestation and the nourishment she supplies to the embryo is 

 analogous to a bed of soil with its various nutrient constituents, 



I had hoped to follow this experiment with others on a larger scale 

 the following year, but was unable to make the attempt until 1893. 

 That year 1 had extraordinary bad luck with my rabbits. I used 

 Angoras and Belgian Hares as before, and out of ten Angora does 

 used, four had no ova in their fallopian tubes after being satis- 

 factorily covered, two had dead ova, and only four produced seg- 



* ' Zool. Soc. Trans.,' vol. 14, Part III, 1897 ; ' Birm. Nat. Hist, and Phil. Soc. 

 Proc.,' vol. 10, Part I, 1896; ' Anat. Anz.,' vol. 12, JNos. 9 and 10, 1896. 

 f ' Eoy. Soc. Proc.,' vol. 48. 



