?ARY SEXUAL CHARACTERS 229 



bryology that determines the asymmetry of the normal 

 male. The occurrence of the male with the two large 

 claws may seem to favor the last interpretation ; for here 

 we find the reverse relation and it does not seem prob- 

 able that such an over-clawed male could have arisen 

 through parasitism, or through disease, although the ar- 

 gument for a genetic change can not be entirely set aside. 



In regard to the other group containing the small ab- 

 errant forms the situation is somewhat different. All of 

 these have started as females, as the location of the ex- 

 ternal genital pores clearly indicates. Yet some of them 

 show also an apparent change towards maleness by 

 the narrowing of the abdomen or possibly a retention of 

 the juvenile condition. Here the change, if it be a change, 

 is in the reverse direction from that shown by most of 

 the intersexes described by Giard and by Geoffrey Smith, 

 since starting as a female the change is towards male- 

 ness, while in the parasitized crabs it is the female that 

 changes towards the male. The different degrees to 

 which the change has taken place in different individuals 

 may seem to indicate disease or parasitism. The ab- 

 sence of further change in the same direction in the next 

 or following molts is not perhaps so favorable to this in- 

 terpretation. But on the other hand the absence of adult 

 crabs of this sort, or at least their infrequency may mean 

 that these individuals do not reach maturity, and may 

 therefore be diseased or infected 2 or that in the adult the 

 full-sized abdomen is attained. These questions must be 

 further investigated before a decision can be reached. 



General and Hypothetical 

 It may seem, as stated above, that some of the changes 

 seen in the fiddlers may be similar in kind to some of 

 those brought about in other crabs by becoming para- 

 sitized. Giard has described several cases in crabs and 



