STUDIES ON EAETHWORMS. 569 



protrusion of the posterior septum of somite xiii^ and thus lies 

 in somite xiv. It is filled with ripe ova and has a goodly- 

 supply of blood capillaries on its wall. It is very conspicuous 

 in the specimens dissected by me, much more so than the 

 ovary, for which 1 should probably have mistaken it had not 

 Bergh's paper appeared ;^ and it is curious that Orley makes 

 no mention of it. 



The funnel of the oviduct (fig. 15,^) projects into somite 

 XIII, close to the point where the ovisac is attached ; and the 

 edge of the funnel is more prominent than is usual. The 

 external pore has already been mentioned, as being on somite 

 XIV (fig. 10, c). 



Orley states that the spermathecse " appear to open to the 

 exterior between the somites ix and x, and x and xi.^^ I can 

 find no trace of spermathecfe, though I have searched for them 

 in some half a dozen specimens, of various stages of maturity ; 

 nor is any trace of them presented in a series of sections 

 through this region of the body. I must therefore conclude 

 that this is an error of observation on his part ; he says no 

 more of them than the above quotation. Can he have mis- 

 taken the ciliated rosettes for these organs, and mistaken the 

 testes for the rosettes ? It seems to me quite probable from 

 his description of the relation of these structures that such is 

 the case ; a portion of a ciliated rosette, removed, teased, and 

 examined, would show mature spermatozoa, which might lead 

 an observer to conclude that he was dealing with a sperma- 

 theca. Again, the shape of the testes, as seen with a lens, 

 might without difficulty be mistaken for ciliated rosettes, 

 which he places in the position occupied by the testes, though 

 he has placed these in the wrong somites. 



The cocoon and spermatophore are so fully described 

 and figured by Orley, that I have nothing to add to his 

 description of these structures. 



His interesting observations on the habits of Criodrilus 



' It is probable, as Mr. Beddard has remarked in a recent number of the 

 • Proc. Zool. Soc.,' that the structure figured aud described by me as the 

 ovary of Microchseta (see this Journal, vols, xxvi and xxvii) is really 

 the " ovisac ;" and that I have overlooked the true gonad. 



