602 OLIGOCHAETA 



worms. It is, however, as I have shown, developed from the septa, and is therefore 

 to be regarded as a coelomic pouch comparable to the sperm-sacs of this and other 

 Oligochaeta. The ovaries are not visible in adult worms. They are obvious enough 

 in young specimens, and occupy the usual position, attached to the front wall of 

 segment xiii. They would be, were they persistent in the adult worm, enclosed within 

 the sac already described. The egg-sac is closely adherent to the anterior of the 

 three diverticula of the spermathecal sac ; its lumen, however, does not communicate 

 with that of the spermathecal sac. 



Libyodrilus violaceus, Beddaed. 



Ii. violaceus, Beddaed, Q. J. M. S., vol. xxxii, 1891, p. 539. 

 Definition. Length, 155 mm.; diameter, 5 mm.; numler of segments, aoo. Colour, dull 

 purplish brown. Clitellum, XIF-XFI. Hal. — Lagos. 



Genus Stuhlmannia, Michaelsen. 



DEFUfiTiow. Setae strictly paired. A median penial process. Spermathecal orifice 

 in XIII. Male pores XVII/XVIII. Ovaries enclosed in sacs. Fenial setae present. 



This genus, like so many others of the Eudrilidae, has only one species. It is, 

 therefore, hard to distinguish generic from specific characters. The most marked 

 external character of the genus is the median penis, whose position is variable and presence 

 even inconstant. I have described the minute structure of this organ above (p. 125). 



The clitellum extends from xiv-xvii (sometimes from xiv-xvii only). 



The female reproductive organs are for this genus, as for most Eudrilidae, peculiar 

 and characteristic. The external pore opens into a large sac, whose walls are at 

 &st very muscular and form a bursa copulatrix ; from this arise two slender tubes 

 which pass round the first mentioned sac and the gut, and then unite with each 

 other to form a small median backwardly directed sac. From the ring which 

 surrounds the gut leads on each side a delicate tube, which presently swells out to 

 form an egg-sac, from which the oviduct leads to the external aperture on the 

 fourteenth segment. 



The position of the ovaries is a matter of doubt, but it seems likely that they 

 are concealed somewhere or other within the system of sacs already described. It 

 is remarkable that in a large number of specimens which I dissected, the egg-sacs 

 of the right side of the body only were fully developed, those of the left side being 

 rudimentary. 



