246 OLIGOCHAETA 



orifices of the spermathecae and the atria, but there is no description to hand of 

 their forms. That they differ from the ordinary setae whose place they take seems 

 probable ; in any case, those accompanying the male pores are arranged differently 

 from the ordinary setae ; Vkjdoysky figures them (8, fig- 4) as lying one in front 

 of the other. 



Genus Clitellio, Savigny. 



Lumbricus, 0. F. Mullee, &c. (in part.). 

 Peloryctes, Leuckaet. 

 Tubifex, d'Udekem (in part.). 

 Pododrilus, Czerniaysky (in part.). 

 ? Psammobius, Levins en. 



Depinitioit. Uncinate seta only present. Dilated hearts in VIII, IX. No prostates. 

 Spermatheca occupies four segments —X-XIII. 



In spite of Clapaeede's account of the structure of this genus and of Lininodrilus 

 they are confounded by Vaillant (6), who leaves out from his generic definition, 

 as well as from the description of the species, Gl. arenarius, the characteristic difference 

 between the two genera, viz. the absence (Clitellio) or presence (Limnodrilua) of 

 prostate glands appended to the effei'ent apparatus, which he does not consider of 

 sufficient importance to be a generic character. In an earlier work (3) Vatllant had 

 already taken up this position, which was accepted by Czeentavsky. My own investi- 

 gations upon Clitellio (70) being entirely confirmatory of Clapaeede, besides adding 

 a few details, emphasizing the necessity, I think, of keeping Clitellio and Limnodrilus 

 separate. I showed, however, an additional point of resemblance between the two 

 genera, i. e. the presence ' of two pairs of specially dilated ' hearts.' In the following 

 table Limnodrilus and Clitellio are compared. It should be mentioned that CI. 

 arenarius is the only species whose anatomy is known'. 



CLITELLIO. LIMNODEILUS. 



Setae. — Entirely uncinate. Ditto. 



Hearts. — Two pairs in vii, viii, both en- Ditto in viii, ix, last only enlarged (not 



larged, stretching through four segments in all species), limited to the tenth seg- 



when mature. ment. 



Integumental blood-capillaries. — Absent. Present. 



Vas deferens. — Comparatively short. Long. 



Spermiducal gland, — Without prostates. "With prostates. 



' 'Clitellio atcr' is not ii Clitellio (see below',. 



