240 IMr. H. J. Carter on Fecundation 



formed before the parent perishes (fig. 4 «). At length, how- 

 ever, tliis talies place, and the progeny, which we shall henceforth 

 call ' spermatozoids,' separate from each other, and finding an 

 exit, probably by rupture, through the effete parent-cell and her 

 capsule, soon become dispersed throughout the space between 

 the two large ovoid cells mentioned, where they thus freely come 

 into contact with the capsules of the twenty-eight remaining or 

 female cells (PI. VIII. fig. 5). 



The form of the spermatozoid now varies at every instant, 

 from the activity of its movements and the almost semifluid 

 state of its plasma; and therefore, if we had not seen it in the 

 parent-cell (fig. 6), it would be very difficult to define what 

 this form really is. Its changes in shape, however, are confined 

 to elongation and contraction, like those of Euglena viridis (fig. 7), 

 and not polymorphic, like those of Amoeba ; hence it is sometimes 

 linear-fusiform or lunular, at others pyriform, short, or elon- 

 gate. The centre of the body is tinged green by the presence of 

 a little chlorophyll, while the extremities are colourless (fig. 7) ; 

 the anterior one bears a pair of cilia, and there is an eye-spot a 

 little in front of the middle of the body, also probably a nucleus. 

 Thus we have a product widely different from the common cell 

 of Eudorina. It is about l-2700th of an inch long, and 

 l-10,800th of an inch broad. 



Once in the space mentioned, the spermatozoids soon find their 

 way among the female cells, to the capsules of which they apply 

 themselves most vigorously and pertinaciously, flattening, elon- 

 gating, and changing themselves into various forms as they glide 

 over their surfaces, until they find a point of ingress, when they 

 appear to slip in, and, coming in contact with the female cell, to 

 sink into her substance as by amalgamation (fig. 5 c, c). I say 

 " appear,^^ because, the female cells as well as the spermatozoids 

 being so small, so numerous, and so nearly grouped together, and 

 there being no point like a microjiylc that I could discover, and 

 the Eudorina continually undergoing more or less rotation, I do 

 not feel so certain of having seen the act of union take place as 

 if there had been only a female cell present with a fixed point 

 for the entrance of the spermatozoids, as in the rcsting-spore of 

 GMofjonium. IJut the act itself does not require to be seen ; for 

 the constancy of this form of Eudorina, the way in which these 

 little bodies arc produced, their plastic nature, and their beha- 

 viour towards the female cells arc quite sufficient to convince 

 those who have given their attention practically to such subjects 

 that they are spermatozoids, and that there can be no other ob- 

 ject in tlieir congregating about the female cells than impregna- 

 tion. If this be not sufficient, their number may frequently bo 

 seen to diminish as they pass backward among the female cells, 



