371 



I would regard them as »prostatesct: although I admit that a portion 

 of the prostate in Perichaeta^ Eudrilus, and other genera, in which the 

 spermduct and the prostate join, is probably the homologue of the 

 »atrium« of Tuhifex: for it receives the spermduct: it receives the glan- 

 dular region or prostate proper, and communicates with the exterior, 

 moreover it is provided with a coat of muscles. But in referring to any 

 of these structures as a whole, »prostate« seems to be the more appli- 



Fig. 4. Trigaster, Acanthodrihis &c. : The prostate has the same structure as in Pon- 

 todrilus, but the spermduct does not communicate with the atrium: it opens externally 



in the next segment. 



cl. 



Fig. 5. Monilig aster : — the glandular prostate-cells seem to be absent; 

 so that we have only an atrium. 



cable term : since by this word is generally understood a glandular 

 structure which secretes a fluid, which is utiHsed in some way or 

 another — how is not thoroughly known in Oligochaeta — in the 

 process of copulation , perhaps for diluting the »sperm-fluid« or for 

 connecting the spermatozoa together, to make a »spermatophore«. But, 

 that these organs have some such function is admitted , and as similar 

 organs having similar functions are called »prostates« elsewhere, it seems 

 better to retain the word in place of tlie ill-defined term »atrium«. 



