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THE AMERICAN NATURALIST [Vol. LV 



To understand the process of insemination of the eggs, 

 and the conditions controlling the number of eggs in the 

 capsule, a little speculation is necessary. It seems as if 

 the processes of fertilization and incapsulation are ef- 

 fected during the emission of the eggs; that when the 

 eggs pass downi the uterus or pass the spermatotheca 

 they are fertilized, and immediately after that incapsu- 

 lated, and that the size of the capsules and the number 

 of eggs present in each capsule are regulated by the speed 

 of the outflow of the eggs. The size of the capsule, as a 

 rule, varies according to the number of the eggs present 

 within the capsule. It seems puzzling, however, when 

 capsules are found without eggs, and with eggs which 

 show no indication of being fertilized, but this abnor- 

 mality is limited to the last part of the nidosomic belt, 

 and is of course so controlled that an entire egg-body 

 may not be deposited without some eggs at least being 

 present, and being fertilized. It is a matter for future 

 observation to determine whether individuals in ova- 

 maturity are cjfpable of depositing normal nidosomes, 

 without being stimulated by an individual in ripe male- 

 phase. It is a question whether the mere pressure of 

 ripening eggs will cause egg-flow. Crozier, 1917&, re- 

 ports, however, that Chromodoris zebra, if left alone, 

 deposits fragments of egg-bodies which are not fertilized. 

 The writer has noted the same phenomenon relative to 

 Eolis olivacea when it is kept alone; but also in this case, 

 as in the case of Chromodoris, no normal nidosomes were 

 deposited. 



The question of cross-fertilization becomes of interest 

 since spermatozoa are found in both genital ducts of the 

 same individual, from the ampulla of the penis niul all the 

 way down the penis to the end of it; from and iiicliidiiig 

 the prostate which surrounds the uterus, to and including 

 the ovo-spermatotheca. If self-fertilization takes place, 

 should there be any shortage of spermatozoa during ova- 

 deposition ? The presence of spermatozoa in the female 

 genital tube is undoubtedly the result of coition and the 



