572 MR FRANK E. BEDDARD ON THE ANATOMY OF OCNERODRILUS. 



The minute structure of the testes calls for no particular description. 



§ Sperm Sacs. 



The sperm sacs are not mentioned by Eisen. They are, however, present in Ocnero- 

 drilus Eiseni, and indicate a closer resemblance to Earthworms than to any Lumbriculid. 



There are in all four pairs of these sacs, situated in segments X, XI, XII, and XIII. 



Each sperm sac consists of a delicate nucleated wall, and its interior is not subdivided 

 by trabeculse as it is in Earthworms. The sperm sacs were in every instance crowded 

 with masses of developing spermatozoa, and they often contained a few — but a very few — 

 Gregarines. The sacs are of rounded but somewhat irregular form ; those of the Xlth 

 and Xllth segments are pressed out of shape by the large " hearts " of those segments. 



The sperm sacs of the Xth segment (fig. 1) are perfectly independent of those of the 

 next segment, and they are also independent of each other, though they nearly come into 

 contact on the dorsal side of the intestine. As already mentioned, each sperm sac is in 

 close contact with, but does not enclose, the testis of its side. Neither does it enclose 

 the funnel o^he vas deferens. 



The sperm sacs of segment XI have the same relations to the testes, and the same 

 absence of any relations to the vas deferens funnels ; they become attached to the septum, 

 dividing this segment from the Xllth by a slender cord which perforates the septum, and 

 is continuous with the sperm sac of segment XII. There is, however, no continuity of 

 lumen between the two sperm sacs, though very possibly this may occur at certain stages 

 of development. 



The sperm sac of the Xllth segment projects through the septum for a considerable 

 distance into segment XIII. The aperture of communication is quite wide. 



It follows from the above description that the sperm sacs of Ocnerodrilus agree in 

 their general form with those of Earthworms, but differ from Earthworms and agree with 

 the lower Oligochseta in the fact that their lumen is not divided into numerous compart- 

 ments by anastomosing trabeculse. 



§ Vasa Deferentia. 



The vasa deferentia commence with the funnels in the Xth and Xlth segments. 

 Generalty the funnels of the vasa deferentia lie opposite to their testes, but in Ocnerodrilus 

 the funnels lie below the testes, which, as already said, extend right across their segment. 

 The simple character of the funnels is shown in Eisen's drawing, which would represent 

 Ocnerodrilus Eiseni as well as O. occidentalis. 



The two vasa deferentia unite before they open on to the exterior, but I am not 

 certain as to the segment in which this junction is effected. In 0. occidentalis it appears 

 to be segment XVI. 



