INFLUENCE OF ENVIRONMENT ON SEX 239 



Experiment y. (Carried on in float cars, Woods Hole.) The largest 

 males which could be found (18 to 22 mm.) were removed from their 

 colonies and transferred to hermit shells in which there were no other 

 Crepidulas. Much smaller males were transferred to the same hermit 

 shells and allowed to attach themselves near the larger. It was of 

 course realized that the male organs of the large specimens would 

 soon degenerate after being transferred but in the meantime their 

 effect on the smaller males could be observed, and their effect while 

 they were in the transition period. Several of the small males were 

 fixed and sectioned from time to time, and the observations on them 

 may be briefly tabulated as follows: 



A. Fourteen days after transferring; 6 normal males, 4 more or less 

 degenerate. 



B. Fifteen days after transferring; 2 normal males, 2 degenerate. 



C. Twenty-two days after transferring; 1 normal male, 4 more or 

 less degenerate. 



D. Thirty-one days after transferring; 2 normal males, 2 more or 

 less degenerate, 2 with evidence of regeneration after degeneration. 



E. Thirty-six days after transferring; 1 normal male, 2 degenerate. 



F. Thirty-nine days after transferring; 1 normal male, 2 with evi- 

 dence of regeneration of testis. A fourth specimen in this lot, not one 

 with which the experiment was started, had secured an attachment to 

 the hermit shell probably after being dislodged from another; it shows 

 evidence of recent male development, undoubtedly caused by its new 

 association with the large (formerly male) specimen on which it was 

 found mounted. 



G. Forty -eight days after transferring; 1 normal male, 1 male with 

 evidence of regeneration of testis. 



H. Seventy-four days after transferring; 1 normal male, 1 male with 

 evidence of regeneration of testis. 



I. Seventy-eight days after transferring ; 5 normal males, 1 immature 

 male. 



Examination of the material from experiment 5 brought out 

 several interesting things: 



Fewer small males degenerated than in experiments where they 

 were completely removed from larger animals; but more than 

 when they were left near large females. 



At the end of thirty-one days a hitherto unobserved phenome- 

 non is discovered. Two specimens from D show very clearly 

 that after having undergone degeneration the testis has devel- 

 oped anew. The accessory male organs do not yet show regen- 

 eration; the penis has disappeared leaving only a small stump 

 and the seminal vesicle has the thick-walled condition assumed 

 when the sperm are being absorbed (see former paper). There 



