304 ANIMAL PARASITES. 



male organs, but not, as Bischoff, Wedl, and others asserted, 

 epithelial structures of the female organs. The less-developed 

 forms occurring in the female genitalia, are also seen in the vas 

 deferens ; the development of the seminal corpuscles within the 

 female organs increases from below (vagina) upwards (uterus and 

 albuminigenc}, and here the sequence of the stages of develop- 

 ment may be very well studied. The seminal corpuscles always 

 move freely in the latter places, and, according to Thompson, 

 never adhere to the inner surface of the female genitalia. The 

 seminal corpuscles of the nematode worms have no filaments, 

 and are motionless. In the nematode worms and all motionless 

 seminal corpuscles of other animals, the filament is replaced by 

 the open space, at which the granular substance has collected, 

 together with the nucleolus. 



When the seminal corpuscles have become mature, their deve- 

 lopment-cells, according to Meissner, often acquire various forms ; 

 hence the pyriform or wedge-shaped seminal corpuscles of Bagge, 

 Keichert, and Von Siebold. By the bursting of the elementary 

 cell, the corpuscle which was previously lying bent in the cell 

 suddenly acquires an extended position, and the cell-membrane 

 is broken through at the point where it is succeeded by the finely 

 granular substance at the open flocculent, thicker end of the 

 seminal corpuscle. With this flocculent end the seminal corpuscle 

 slips forth, but the whole does not follow. 1 The cell-membrane 

 remains sitting like a cap upon the bell-shaped, closed portion of 

 the seminal corpuscle. The thickness of the flocculent end of 

 the seminal corpuscle now stands constantly in a corresponding 

 relation to the opening of the vitelline membrane (Keber's 

 micropyle), fixes itself to this and penetrates into it, during 

 which the cap-like, revolute, cell-membrane becomes a pre- 

 liminary adhesion of the seminal corpuscle to the egg, although 

 the flocculent end of the seminal corpuscles is sufficient for 

 the actual adhesive attachment to objects (as is proved, for in- 



1 Amongst the seminal cells in the male generative organs, and, although rarely, in 

 the lowest parts of the female organs, we find, together with the true seminal corpuscles, 

 smaller oval corpuscles of ^- Q " in diameter, without distinct nuclei or nucleoli; they are 

 pretty strongly refractive, have a smooth surface, and except in the absence of the 

 nucleolus are tolerably similar to the nuclei of the other original seminal cells. 

 Bischoff, certainly erroneously, takes them for the true developed seminal corpuscles ; 

 Thomson, ou the contrary, regards them as abortive corpuscles, which is more pro- 

 bable. 



