FECUNDATION OF NEMATOIDA. 303 



semicircularly in accordance with the dimensions of the cell-wall, 

 because it has no room when extended. 



According to Thompson, the outer part of the seminal cell, 

 which in the male forms a nearly homogeneous, finely molecular, 

 layer, becomes clearer and thinner on the side where the seminal 

 corpuscle afterwards lies, but at the opposite side, that is, the 

 one situated nearer to the open end of the future seminal cor- 

 puscle, the molecular contents accumulate in greater quantity. 

 On the application of water, or even of saliva, the finely granu- 

 lated outer layer becomes converted by imbibition into a large, 

 clear, vesicular mass, like sarcode. The granular envelope, which 

 gives occasion for the formation of this clear mass, is a perfectly 

 natural formation, and is, in fact, the residue of the original 

 radiate, but afterwards granular substance, which occurs in the 

 segments of the original seminal cells. 



The nucleus, that is to say the inner, strongly refractive part 

 of the seminal cell, becoming gradually converted into a flask- 

 shaped or bell-shaped structure, forms the seminal corpuscle. 

 According to the side from which this seminal corpuscle, which 

 is bounded by a dark, double outline, is examined, its appearance 

 varies. When seen from above or below it is nearly circular; 

 from the side and in profile (the usual position) it appears in its 

 earlier stages semicircular, as if open on one side and furnished 

 with a finely granular, sarcode-like mass, which swells up in 

 water, extends into the interior, and contains a distinct point or 

 nucleolus. In water, and also, although rarely, even without 

 the application of any fluid, this sarcode-like mass issues in the 

 form of a vesicle or drop from the open side of the seminal cor- 

 puscle. A seminal corpuscle unaltered by imbibition occupies 

 somewhat more than the half of its development-cell, and is, 

 therefore, cap-shaped, or semicircular. Perfectly developed 

 seminal corpuscles, which occur in the upper parts of the ovary, 

 have lost all traces of envelopes and resemble an elongated tube 

 closed at one end, and furnished at the other with a somewhat 

 enlarged mouth ; they have become flask-like or glove-like. They 

 still possess the dark, double outline, but it is somewhat thinner, 

 and the finely granular mass with the molecules also exists at 

 the open end of the seminal corpuscle. Intermediate steps 

 between the tw r o forms are met with. The ordinary form of the 

 seminal corpuscles occurring in the female generative organs is 

 that of a cupola or bell. They are certainly the product of the 



