No. 632] SECONDARY SEXUAL CHARACTERS 233 



ductive " glands" in other animals suggested the possi- 

 bility that the secondary sexual characters of fiddler crabs 

 might be affected if the crabs were fed on the organs of 

 the opposite sex during the period of regeneration of the 

 large claw. Male fiddlers whose large claw had been 

 previously removed, were fed exclusively, and at inter- 

 vals of two or three days, on the ovaries of female spider 

 crabs. The fiddlers were kept until they moulted about 

 a month or two later. The new claw showed all the char- 

 acteristic features of the normal large claw. Its regen- 

 eration had not been affected by the character of the food. 



Female fiddlers, one of whose claws had been pre- 

 viously removed, were fed on the testes and the ducts 

 leading from them of the male spider crab. Other 

 females were fed on what appears to be a large gland in 

 the posterior part of the abdomen of the male. No effect 

 on the regenerating claws were observed. 



These negative results do not show that there is no 

 hormone in the gonads of the crab that affects the sec- 

 ondary sexual characters, for even if there were such, it 

 might not be able to produce its effect through the diges- 

 tive tract. Only positive results of this kind would be 

 important but none were obtained. As the results were 

 entirely negative they need not be further described. 



A more promising test consisted in boring a hole in 

 the carapace of the male fiddler and inserting pieces of 

 the ovary of the female fiddler. Conversely for the 

 female. There are certain implications in Geoffrey 

 Smith's views that seem to imply that male tissue can 

 not survive and grow in an individual with female metab- 

 olism, and perhaps conversely for the male. The small 

 grafted pieces often become lost, and it is difficult to de- 

 termine later by means of sections how far the tissues 

 degenerate and how far they become implanted and grow. 

 I have not had the time to carry out a detailed study of 

 the sections, but they seem worthy of further examina- 

 tion. No effect on the claws were produced. 



