330 



Ipestris. [ 



species satisfies me that it must be considered only as a centralized 

 spermatheca analogous to the spermathecae in Rhynchelmis Iwiosella. 

 It is true that the walls of the spermothecal atrium are glandular, 

 but the secretions of the cells must serve a different purpose than 

 the albumen glands in Rhynchelmis and Lumbriculus. On each 

 side of the spermathecal atrium are seen the true receptacula 

 seminis or spermathecae, slender, branched ducts (Fig. 7), opening 

 interiorly close together, but not separately (Fig. 8). The branched 

 spermathecae generally contained spermatozoa, but I have never 

 observed in them any spermatophores. . 



In the undeveloped spermathecal atrium no branched sperma- 

 theca are seen; these develop later, only at the full maturity of the 

 worm. In one instance I found an interior porus in the free end of 

 the spermatheca similar to the one described by Vejdovsky in the 

 receptacula seminis of Rhyjichelmis limosella. The object of such 

 an opening is not at present understood. 



Considering this central spermatheca in Sutroa in connection with 

 the two spermathecc-e in Rhynchelmis, two theories are admissible. 

 One is that in Sutroa one of the spermatheca has failed to develop, 

 and that the remaining one has become central by being moved 

 towards the central ganglion, which latter it considerably displaces. 

 The other theory is, that in Sutroa the two spermatheca are repre- 

 sented by or homologous with the pairs of branched spermathecal 

 sacs opening into the spermathecal atrium. The latter, then, is 

 only an infolding of the body-wall, deep enough to cause the sper- 

 mathecae to become merely appendices to the central spermathecal 

 sac or atrium. I believe this latter theory to be the correct one. 



Somewhat similar spermathecal branches or pockets are found in 

 Anachaeta as well as in Tygmceodrilos, but here the forma- 

 tion IS a different one, the appendix being simply a pocket 

 and not a separate organ. As regards the morphological structure 

 of the spermathecal branches, it is quite similar to that of the same 

 organs in Sutroa rostrata, and described by me elsewhere. 



Albumen Glands. In Rhynchelmis limosella as well as in Lum- 

 briculus, we meet with a central albumen gland in one of the 

 somites between the spermatheca and the spermiducal pores. In 

 Sntroa^ rostrata I ascribed glandulous properties to the spermathe- 

 cal atnum, considering it homologous with the albumen gland in 

 Rhynchelmis. 



