SPERMATOPHORES AS A MEANS OF HYPO- 

 DERMIC IMPREGNATION. 



C. O. WHITMAN. 



Although it is well known that spermatophores are of very 

 general occurrence among the invertebrates, and even among 

 many vertebrates, the assertion that, as a perfectly regular and 

 normal affair, in animals as highly organized as the leeches, 

 they represent an injecting apparatus, by means of which the 

 spermatic elements of one individual are forced throngJi the body- 

 wall of another, at any point wJiatsoever, may appear almost in- 

 credible, even when supported by direct observation many times 

 repeated on different species. That such is certainly the case, 

 however, is very easily demonstrated, and any one can verify it 

 as often as he likes on almost any species of Clepsine that hap- 

 pens to be accessible. The observations to be presented in this 

 paper will make this fact abundantly evident. 



But what becomes of these spermatic injections } Do they 

 ever reach the eggs and fertilize them } and if so, is this the 

 normal method of bringing the sexual products together } Al- 

 though I cannot affirm this as a positive certainty, the evidence 

 seems to me to fall but little short of being conclusive. I have 

 studied closely the habits of these leeches in Europe, Japan, and 

 America, and with especial reference to settling the question of 

 when and how impregnation is effected. Long-continued obser- 

 vation under most favorable circumstances has never given me 

 so much as a single indication that the genital pores are ever 

 united in the act of copulation. On the other hand, the plant- 

 ing of spermatophores on the surface of the body at any point 

 that happens to come first, is a common occurrence, which one 

 may often see repeated several times in the course of a few 

 hours by the same individual. I have followed the track of 

 the spermatozoa from the point of penetration to the coelomic 

 cavity in which the ovaries lie, but I have not pursued the 

 subject far enough to determine when or how the spermatozoa 

 pass through the wall of the ovisacs. That spermatozoa get 



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