No. 3.] SPERMATOPHORES. 395 



process takes place in D. tccniatus is very readily obtained by merely 

 placing a considerable number of individuals of both sexes in a small 

 quantity of sea-water, as in a watch-glass. Under these circumstances, 

 it is noticed, even a very short time after the animals have been placed 

 together, that here and there a male is attached, by means of its penis, 

 to the body of a female. In these cases, the terminal, conical portion of 

 the penis is protruded through the generative pore, and is passed into the 

 skin of the female ; spermatozoa are then seen to have passed, from the vesi- 

 culcBseminales, through the skin of the female, and to he accumulating them- 

 selves into a mass immediately beneath the perforation made by the penis. 



" There seems to be no localization of the spot ac which spermatozoa 

 can be introduced into the female. The penis can obviously be inserted 

 into the skin at any point, as is shown by the fact that, in the cases actu- 

 ally observed, the point selected was sometimes in the region of the 

 neck, in other cases far back in the body of the female, and in other 

 cases near the middle of the body. 



" The act of copulation has no relation to the maturity of the ova of 

 the female, nor is it prevented by the fact that the female has already 

 received an ample supply of spermatozoa by a preceding operation. It 

 was extremely difficult to discover any female, in which ovaries were 

 recognizably developed, which did not contain large numbers of sper- 

 matozoa in its body-cavity. These were observed in almost any part of 

 the body of the animal, their position being probably partly dependent 

 on the manner in which fertilization had been previously effected. The 

 spermatozoa show, however, a great tendency to accumulate into a large, 

 compact mass, situated in a space on the ventral side of the stomach. 

 In some cases it was observed that the female was receiving spermatozoa 

 simultaneously from two males ; in others that while, for instance, ferti- 

 lization was being effected near the posterior end of the body, a great 

 mass of spermatozoa (obviously obtained on a previous occasion) was 

 visible at the anterior end of the body. In many cases the females were 

 enormously distended with spermatozoa, which could hardly have been 

 all received at one time. 



" The common occurrence of great numbers of spermatozoa in the body 

 of the supposed female might suggest that D. tceniatus was hermaphro- 

 dite. Such a supposition is rendered sufficiently improbable by the 

 following considerations : (I) That no other species of Dinophilus is 

 known to be hermaphrodite ; (II) that the process of fertilization was 

 frequently observed in D. tceniatus ; (III) that the spermatozoa so con- 

 stantly seen in the female of the same species were, without exception, 

 ripe and actively moving, no trace of spermmorulae or unripe sperma- 

 tozoa being discernible. Such stages in the development of the sper- 

 matozoa were never missed in any adult male individual." 



