414 TRANSACTIONS OF SECTION D. 



i 



12. Report on the Mammalian Fauna in the Miocene Deposits of the Bugti 

 Hills, Baluchistan. — See Reports, p. 127. 



13. Twenty-first Report on the Zoology of the Sandwich Islands. 

 See Reports, p. 128. 



14. Report on Zoology Organisation. — See Reports, p. 127. 



15. Report on the Occupation of a Table at the Marine Laboratory, Plymouth. 



See Reports, p. 129. 



16. Fourth Report on Experiments in Inheritance. 

 See Reports, p. 125. 



17. Report on the Formulation of a Definite System on which Collectors 

 should record their Captures. — See Reports, p. 126. 



18. Some recent Work on Sex. By Geoffrey Smith. 



In a communication made to the British Association last year the author put 

 forward a theory to account for the effect of the parasite Sacculina upon the 

 sexual characters of its host, Inachus, according to which the development of the 

 adult female characters in infected individuals of both sexes was held to be due 

 to the production in excess of a yolk or fatty material in the blood similar to 

 that which is stored in the ovary of a normal adult female. It was shown that 

 the roots of the Sacculina actually take up such a fatty substance from the blood 

 of the host, and it was supposed on the analogy of an immunity reaction that the 

 fixation of the fatty material by the parasite stimulated its constant production, 

 and that the presence of this substance constantly circulating in the blood was 

 the stimulus for the production of the female characteristics. Evidence bearing 

 on this theory and to some extent confirming it has been obtained by G. C. Rcbson 

 at Naples. Following and extending the observations of Heim, he finds that in 

 normal Inachus the blood may be coloured orange or pink by the presence of a 

 lipochrome in solution. Lipochromes invariably accompany fatty substances, in 

 which they are soluble ; we may therefore suppose that when lipochrome is pre- 

 sent in the blood it is accompanying fatty materials. Now it has been found 

 that the presence of lipochrome in the blood is particularly characteristic of 

 female crabs at the time that the ovary is maturing, when a transference of fatty 

 material and of lipochrome to the ovary from the liver is observed to be taking 

 place. In Inachus of both sexes infected with Sacculina we also get a develop- 

 ment of lipochrome in the blood equal to that which occurs in breeding females. 

 This fact is therefore in complete agreement with the theory outlined last year. 

 The matter is, however, complicated by the fact that lipochrome is developed in 

 the blood of normal Inachus of both sexes which are about to moult, so that 

 it cannot be held that the mere presence of the lipochrome in the blood is the 

 stimulus for the development of the female characters. The proof, however, is 

 furnished that the presence of Sacculina profoundly influences the fat metabolism 

 of its host. Work is proceeding on these lines. Some observations have also 

 been made by the author upon the fluctuations in growth of the comb of fowls 

 which show the close connection between fat metabolism and the development 

 of the female characteristics. 



