1906.] AVORMS OF THE THIRD TANGANYIKA EXPEDITION. 207 



among those Oligoclifeta lying on the border-iine between the 

 purely aquatic forms, like the Lunibriculidse, and the purely 

 terrestrial earthworms, such as Lumhricus. Both these species 

 have been obtained either from the depths of the lake or from 

 the roots of plants gi-owing on its margin. The two remaining 

 species are Eudriline genera, like the majority of Ethiopian 

 terrestrial Oligochaeta; and, like the earthwoi'ms of Tropical 

 Africa generally, they are semiaquatic in habit, dwelling in very 

 wet places not far from the shores of the lake. 



StuMmannia inermis, sp. n, 



A number of specimens of a worm dug up in the close neigh- 

 bourhood of the shores of the lake from sandy mud seem to me to 

 belong to an undescribed species of the genus Stuhlmannia. 



The salient character of this species, viz., the occasional absence 

 or, if present, feeble development of penial seta3, has suggested its 

 name. At the same time none of the considerable number of 

 examples collected by Dr. Ounnington is fully mature ; so that it 

 is conceivable that the penial setse ai'e as yet undeveloped. Never- 

 theless this view seems to me to be unlikely. The penial sette are 

 often visible in earthworms when other parts of the sexual organs 

 are in a comparatively undeveloped state. On the latter view 

 therefore I venture to regard the species as new, for it seems 

 hardly likely that of three individuals selected at random for 

 anatomical study the penial setse should be fortuitously absent or 

 lost in the course of the dissection or the preparation of micro- 

 scopic sections. In one specimen, however, they were present, but 

 feebly developed. They are hollow in transverse section. 



The genus Stuhlmannia is one of the most prevalent African 

 genera of Eudrilidje, and the present species does not differ from 

 the numerous examples of other species which 1 have had the 

 oppoi-tunity of examining in the general outward appeai-ance. It 

 is a long thin worm of about the size of Stuhlmannia variabilis. 

 The largest example measured 138 mm. All of the speci- 

 mens were immature and showed neither clitellum nor a penis. 

 The spermathecal and the atrial pores were, however, plainly 

 visible and separable from each other by their characters as well 

 as, of course, by their position. The spermathecal pore on the 

 xiiith segment was on a raised protuberance. The atrial pore on the 

 boundary-line of segments xvii./xviii. was a raised protuberance 

 with a crater-like depression in the middle. The ventral setce of 

 the xviith segment were missing, otherwise both pairs are present 

 in the genital region as elsewhere. The oviducal pores are to the 

 inside of the lateral pair of seta? on the xivth segment. The setfe 

 are closely paii'ed and upon the ventral surface of the body. 



The colour of the worms (in formol) is a dark bluish purple, 

 so general a hue among earthworms and the Eudrilidse in par- 

 ticular. 



The gizzard lies in segment v. The calciferous glands, which 

 have the same rudimentary character as in other members of this 



