230 C. L. TURNER. 



obtained thus far in the Arthropods does not favor the assumption 

 of control of the direction of development of the secondary sexual 

 characters by secretions from the gonads. However, the 

 prevalence of parasitism in the forms studied could not be 

 overlooked and parasitism of the gonads was stated as a possible 

 cause for the intersex condition. More weight was attached to 

 the possibility of genetic disturbances being the important factor 

 for reasons to be stated later. In the aberrant specimens 

 described here parasitism was variable in its occurrence among the 

 intersexes even to the point of being non-existent in a considerable 

 number. Parasitism, either as affecting the body directly or the 

 secondary sexual characters indirectly through the gonads 

 cannot, therefore, be considered seriously. 



If the specimens described here were truly hermaphroditic it 

 should be possible to find some traces of testicular tissue within 

 or near the ovaries. All specimens seem to have been functional 

 females and at a season when they might be expected to carry 

 eggs or embryos they were doing so. A considerable number of 

 specimens have been carefully dissected and macroscopic and 

 microscopic examinations made but with the result of finding 

 nothing that might be called testicular tissue. Testicular tissue 

 may be present but it has not been found as yet. 



The possibility that some environmental influence such as 

 peculiarities of temperature or chemical substances in solution 

 may have been causing the aberrancies can be tested by removing 

 specimens from Lake Delavan while they are still in the egg stage 

 and rearing them under changed conditions. Such a study is on 

 the program for the coming spring. 



Peculiar or accidental embryonic development without 

 attendant environmental influences to account for them might be 

 considered to account for a small number of intersexes but this 

 factor could scarcely be invoked to account for as large a propor- 

 tion as 88 per cent. 



The suggestion that changes in genetic constitution have been 

 the underlying cause seems by the process of elimination to be the 

 logical choice and indeed there is considerable direct evidence to 

 support such a claim. This possibility was suggested in the cases 

 of Cambarus profrinquus previously described for the reason that 

 intersexes from the same localities showed a remarkable degree of 



