582 FRANK E. BEDDARD. 



be proved ; but theu it will have to be farther proved that the 

 duct of that sac up to a point beyond the '^oviducaP^ orifice 

 is also derived from the coelomic sac. Now, Horst says (7, p. 

 233) that the muscular layer of the spermatheca becomes very 

 thick near to the point of opening of the ovarian duct (= my 

 " oviduct of Segment 13 ^'). This looks as if the true sperma- 

 thecal invagination began, or rather ended, at this point. If 

 so, it would be reasonable to speak of the tube in question as 

 an oviduct, whereas if it were merely a portion of the coelomic 

 sac it could hardly be termed an oviduct, but rather an exten- 

 sion of the said sac forwards. 



It is clear that two pairs of ovaries and oviducts formerly 

 existed in earthworms ; not only do they occasionally occur as 

 a sport (see my remarks upon varieties of Peri onyx), but they 

 occur normally in Phreoryctes. Considerable traces of the 

 missing parts are met with in embryos of Lumbricus and 

 Acanthodrilus. Dr, Horst has overlooked these facts, some 

 of which were known when he wrote (7, p. 239), " Chez 

 tous les genres d'Oligochetes, on n'a trouve jusqu^ici qu'une 

 paire d'ovaires." To return to the immediate subject of 

 discussion, it seems probable that the large sacs termed sper- 

 mathecse in Eudrilus and Teleudrilus correspond to the 

 coelomic pouches of Libyodrilus and the other forms. The 

 question is how much of them corresponds ; it may probably be 

 safely assumed that up to the point of opening of the ovi- 

 ducts there has been an epidermal invagination ; but beyond 

 that inference I do not consider it safe to go at present. 



VII. Definition of Genus and Species. 



Genus Libyodrilus, F. E. B.^ 



Nephridia paired, but connected with a network of tubes 

 ramifying in the integument; those of some of genital seg- 

 ments disappear in mature worms, but network remains. A 

 large unpaired sac opening on Segment 13 extends through 

 ' I have briefly characterised the species in * Proc. Zool. Soc.,' 1891, p. 172. 



