NEW GENERA AND SPECIES OF EAETHWOEMS. 265 



the stages of sexual maturity. In some specimens they were 

 fully as long as they are figured by Levinsen;i in others they 

 were no longer than I have already figured them ^ in the present 

 species. These outgrowths are undoubtedly penes, as Levin- 

 sen thought. I have found that the vas deferens traverses 

 them, opening on to the exterior at about the middle. But I 

 imagine that they must perform some other function in addi- 

 tion to that of serving as intromittent organs for the sperm ; 

 they are so altogether out of proportion to the fine canal 

 which perforates them ; and besides, there are no correspond- 

 ingly large organs to receive them during copulation. The 

 structure of the penis is displayed in fig. 19. In cross section 

 they are roughly semicircular ; the ventral surface is, however, 

 not flat; as shown in fig. 19, it has a broken surface. Here 

 and there are deepish depressions, caused apparently by the 

 unequal contraction of the muscular fibres. There was no 

 regular infolding of the two edges of the penis, such as Levinsen 

 figures in Siphonogaster segyptiacus. 



The under surface of the penis is also broken by deep de- 

 pressions, which serve probably as suckers. I generally found 

 two of these near to the attachment of the organs to the body- 

 wall ; but there are others all along the penis, which are not as 

 a rule so marked ; from the bottom of these depressions arise 

 the setse. In sections through the penis they have the appear- 

 ance represented in fig. 19. The epithelium which lines these 

 semicircular pits rs very glandular ; the cells are deeply stained, 

 and, are laden with spherical granules. The setse spring from 

 the bottom of these pits ; the shape of the set<e is illustrated in 

 fig. 21. So far as I could ascertain all the setse arose from 

 pits, but these pits are of very various sizes ; as a rule they are 

 inconspicuous, not visible at all, in fact, by the unarmed eye ; 

 but there are usually two large ones near to the base of the 

 penis, as figured in fig. 18, Sv. ; these, however, are not always 

 present, or are, at any rate, not always obvious. The epithe- 



' Loc. cit., tab. vii, figs. 1 and 2. 



^ "On an Earthworm of the Genus Siphonogaster from West Africa," 

 'Proc. Zool. Soc./ 1891, p. 48. 



