40 THE TESTIS AND ITS SECRETION, &o. 



and in many instances small spherical cells are thrown off from 

 this, which are quaternary, and probably spermatozoa! cells. 

 In the cuirassed and digging Macroura these tertiary cells are all 

 armed with three seta?, many times longer than the body of the 

 cell. In the prawn these setaa are short and truncated. 



Throughout the whole course of the lower part of the seminal 

 tube there may be observed during the active state of the gland, 

 and while the seminal cells are being produced, a large quantity 

 of albuminous matter in small irregular masses floating among 

 the cells in an aqueous fluid. I am induced to believe that the 

 cells derive their nourishment from this matter. 



In the upper part of the tube, where the cells are small and 

 comparatively few in number, this matter is in small quantity ; 

 but in the lower part of the tube, where the cells are more nu- 

 merous, more developed, and in a more active condition, it exists 

 in the greatest abundance. Still lower down in the vas deferens, 

 where the cells are in a state of satiety, and are in fact absorbing 

 principally their own external wall, preparatory to bursting, it 

 again diminishes in quantity, and disappears. 



This albuminous matter would appear to result from the debris 

 of dissolved cells. It is more abundant in the Brachyura than in 

 the other forms of Crustacea, in accordance with the greater 

 abundance of seminal cells.* 



H. D. S. G. 



* An abstract of more extended observations on the subject of this chapter was published 

 in the Ed. Phil. Journal, Oct. 1843. 



