258 FRANK E. BEDDARD. 



remarkable striated membraue which I shall refer to directly 

 in describing the ova within the egg-sacs. 



The oviduct has been incidentally referred to in the fore- 

 goingdescription; it opensinto the egg-sac and into the coelomic 

 space continuous with the perigonadial sac; it is a short tube, 

 and passes straight to its opening upon the 14th segment ; it is 

 not twisted upon itself, as is the oviduct of Eudrilus. The 

 oviduct has fairly thick muscular walls, the fibres of which are 

 for the most part arranged in a series of rings round the tube, 

 and a lining of columnar ciliated cells. The calibre of the 

 oviduct diminishes gradually from the funnel to the external 

 aperture. 



The egg-sacs are also situated in the 14th segment: the 

 septum dividing this segment from the one in front is entirely 

 or largely absent; but the position of the egg-sacs within the 

 14th segment suggests that they lie near to where the anterior 

 wall of that segment should be. The interior of the egg-sacs 

 is divided up by trabeculse anastomosing with each other into 

 a series of very small compartments, only just broad enough 

 to contain a single ripe ovum; the compartments, as in other 

 earthworms, are lined with small peritoneal cells (see fig. 29). 



The mature ova do not present any noteworthy differences 

 from those of Hyperiodrilus. 



Spermatheca, — As in Hyperiodrilus, there is only a 

 single spermatheca present, which lies on the right side of the 

 body — the opposite side, therefore, to that which the sperma- 

 theca occupies in Hyperiodrilus. The spermatheca in 

 Heliodrilus is a large conspicuous organ, which can be seen^ 

 on a dissection of the worm, to reach on to the dorsal side of 

 the gut ; it contrasts, therefore, with the very small sperma- 

 theca of Hyperiodrilus. As in the latter worm, the appa- 

 rent bulk of the spermatheca is increased by a prolongation of 

 the perigonadial sinus which partially surrounds it; but the 

 arrangement of this sinus in Heliodrilus is very curious, and 

 quite unlike that of Hyperiodrilus. But before describing 

 the sinus I will direct attention to the characters of the 

 spermatheca itself, which differs in certain points from the 



