490 MR. F. E. BEDDARD ON THE [DcC. 4, 



appeared to be equal and stouter than the more anteriorly situated 

 trunks. The description which Zenger gives of the reproductive 

 organs is, as he himself admits, imperfect. The most important 

 point which he mentions is the presence of spermatophores, which 

 were little known at the time when he wrote. There is nothing 

 in his description of the reproductive organs to distinguish Peloryctes 

 inquilina from Glitellio ater. 



On the whole the identity or non-identity of Peloryctes inquilina 

 with Clitellio ater must be for the present regarded as an open 

 question, though I am disposed to think that they are identical. 



§ 2. Anatomy of Clitellio. 



Generative Organs. — Claparede's account of the reproductive 

 organs of Clitellio is by no means complete. 



He has confounded, as so many writers have done, the testes 

 with the vesiculce seminales ; the former organs are not described 

 by Claparede. I find that the testes differ in no important particular 

 from those of Tubifex ; they lie (see Plate XXIII. fig. 1), as in 

 that genus, in the 10th segment, into which open the funnels of the 

 vasa deferentia ; each organ is long and narrow, somewhat swollen 

 at the base of attachment to the body-wall. The vesiculce seminales 

 (testes of Claparede) were not, judging from Claparede's description, 

 fully developed in any of the specimens studied by me. The 10th 

 segment in one specimen contained a mass of developing spermatozoa 

 about equal in size to a similar mass occupying a large portion of 

 segment 11. In the latter case, however (Plate XXIII. fig. 3), 

 the mass of developing spermatozoa was enclosed in a thin-walled sac 

 abundantly furnished with blood-vessels which was confined to this 

 segment, and did not extend back through several segments. 



The generative system of a young example of C. arenarius is 

 depicted in Plate XXIII. fig. 1 ; it will be seen that the funnels of the 

 vasa deferentia open into the 1 0th segment, but the cells of which they 

 are composed are not ciliated. The vasa deferentia pass in a 

 slightly sinuous course to the atrium, which opens externally, not 

 far from the posterior border of the 1 1th segment. The atrium in 

 the undeveloped condition is lined by a simple non-glandular columnar 

 epithelium ; it is invested externally by a thin coat of muscles, 

 outside of which is a tolerably thick layer of glandular peritoneal 

 cells. The spermathecce lie in the 10th segment, and at this stage 

 are simple pyriform vesicles. Upon the anterior face of the septum 

 which separates the 11th from the 12th segment, and corresponding 

 exactly in position to the funnel of the vasa deferentia, is a disk- 

 shaped layer of columnar cells, which is evidently the oviduct ; the 

 cells at this stage are, like the cells of the vasa deferentia funnels, not 

 ciliated. In the sexually mature animal the oviduct-funnels are 

 extremely conspicuous (fig. B & Plate XXIII. fig. 2) cup-shaped 

 organs, with abundant cilia. At the time that I made this observa- 

 tion, I was not acquainted with any observations upon the structure 

 of the Tubificidae later than those of Vejdovsky ' ; I concluded 



^ System u. Morph. d. Oligochaeten. Prag, 1884. 



