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



$ Spermathecce. 



Eisen did not record the presence of spermathecse in Ocnerodrilus occidentalis, but 

 subsequently found these organs to be present in several other species of the genus from 

 Central America. This discovery led him to suspect that the organs in question must 

 have been overlooked in O. occidentalis. This supposition may not be necessary, for 

 these organs certainly do not exist in Criodrilus lacuum [see Rosa, 12] and in Lumbricus 

 Eiseni and Allolobophora constricta; possibly also a species of Perichceta has no sperma- 

 thecce [Beddard, 4], Ocnerodrilus Eiseni has a single pair of spermathecse in the VHIth 

 segment, which open on a line with the ventral pair of setse into the furrow which 

 separates this segment from the Vllth. 



The spermathecse (fig. 6) are a pair of spherical sacs, without any trace of a diverticulum. 



I found them to be absent in some of the specimens which I examined ; and this 

 fact suggests that they may really occur in O. occidentalis and have been over- 

 looked. The specimens of 0. Eiseni in which I found spermathecse were fully mature, 

 with the exception of the clitellum, which was quite undeveloped. On the other hand, 

 examples with a fully formed clitellum showed no traces of spermathecas. This is some- 

 what remarkable, as one is inclined to associate the presence of a clitellum with complete 

 maturity of the other organs belonging to the reproductive system. It is possible that 

 this relation is only an accidental coincidence. The absence of a diverticulum is to be 

 noted in relation to the affinities of the worm. Among Earthworms, all the genera 

 included in my family [3] Cryptodrilidas possess one or more diverticula appended 

 to the spermathecse ; and it is with this family that Ocnerodrilus would have to be 

 associated if it were definitely referred to the terrestrial Oligochseta. The absence of 

 diverticula is therefore a point of resemblance to the Lumbriculidse, Phreoryctidae, and 

 other families of aquatic Oligochseta.* 



§ Ovaries. 



The position of the ovaries in Ocnerodrilus Eiseni appears to be very different from 

 that of 0. occidentalis. In the latter they occupy a very unusual position, in their seg- 

 ment being situated upon its posterior wall ; they are stated to lie in the Xllth segment 

 (Xlth setigcrous) on the mesentery, between that and the XHIth. Among Earthworms, 

 Acanthodrilus annectens and A. multiporus are the only species known in which the 

 ovary lies on the posterior wall of the segment. Nor is this a point of resemblance to 

 the Lumbriculidse, for Vejdovsky has figured [15] both in Phreatothrix and Claparedilla 

 the ovaries as attached to the anterior wall of their segment, which is here the Xlth.t 

 In Ocnerodrilus Eiseni the paired ovaries occupy the position which they are found to 



* I am inclined to think that Rosa's failure to find sperrnatheca) in Microscolex dubius may be due to the fact that 

 they are only, as in Ocnerodrilus, present for a short period. 



t Vkjdovsky's figures of Phreatothrix [15, pi. xi., figs. 18, 19] show the Xlth as the ovarian segment, but his table 

 on p. 132 states the Xth segment. 



