1902.] FEMALE ORGANS OF EUDRILUS. 93 



conducting sacs on to the exterior by a median unpaired pore. 

 Of this there is no trace in Uiodrilus, which therefore, so far, is 

 more closely allied to Nemertodrllas than to any other form, whose 

 anatomy has been adequately studied. But in Nemertoclrilus the 

 large sac, which is clearly equivalent to the spermathecal sac of 

 Eudrilus and other genera, is permanently open into the cavity of 

 segment xiii. This represents an immature condition such as is 

 transitory in Eudrilus. 



Text-fig. 19. 



OV \0d. 



Ro. 



XIII XIV 



Diagrammatic representation of female reproductive system of 'Eudrilus. 



D, gland appended to spermathecal sac ; Od., oviduct ; Ov., ovary ; 

 Eo., receptaculum ovorum ; Sp., spermathecal sac. 



The accompanying diagram (text-fig. 19) will therefore re- 

 present more accurately than the hitherto published figures the 

 distinctions between the difterent regions of the egg-conducting 

 apparatus in Eudrilus. There are two other points with which 

 I wish to deal before leaving the female efferent apparatus. In 

 the first place, I have found in these immature worms no trace of 

 the " oviducal gland " attached to and opening into the sperma- 

 theca in adult examples of the worm. The second matter has to 

 do with the ovaries and the sacs in which they are enwrapped. 

 It is noteworthy that in these young worms the ovary was many 

 times larger than the testes ; and that, while the latter showed no 

 developing sperm in their neighbourhood or in the sperm-sacs, 

 the cells of the ovary contained some very large and nearly fully 



