1906.] WORMS OF THK THIRD TANGANYIKA EXPEDITION. 209 



round the intestine ; but whether the two unite above or not, I 

 am unable to say. The " bursa copulatrix," or terminal chamber 

 of the spermathecal sac which opens directly on to the exterior, 

 may or may not communicate directly with the chamber containing 

 the ovaries. I have no evidence of the communication if it exists. 

 But in any case the sac in which the ovaries lie is different from 

 what is to be found in ;S'. vaj'iabilis*. 



In the present species of StiMmannia the entire bursa copu- 

 latrix lies within a large sac, which reaches from septum to septum 

 of the xiiith segment and completely roofs in the bursa. In this sac 

 attached to the front wall of the segment I have found one ovary. 

 There is no question here as in S. variabilis of a small sac enclos- 

 ing the ovary and communicating by a slender duct with the 

 spermathecal sac and its circumoesophageal diverticula. For 

 this reason I regard S. inermis as a distinct species from 

 S. variabilis. 



Dr. Michaelsen's recently described species StiMmannia 

 asytnmetrica t is apparently not to be confused with the present 

 species, as indeed the different habitat would lead one to infer. 

 That species has no penial setfe at all. Considering that the 

 specimens investigated by Dr. Michaelsen were in a more advanced 

 stage of sexual matui-ity than those of S. inei-mis, penial setee, if 

 present, would have been surely visible in some at least of the 

 many specimens in Dr. Michaelsen's hands. But there is, further- 

 more, the important difference that the asymmetry in Dr. Michael- 

 sen's new species is carried to a greater extent than in that described 

 here ; for the oviduct, receptaculum, and ovary are entirely 

 aborted on the left side of the body, the right hand efferent 

 apparatus of the gonads alone remaining. This feature serves at 

 once to differentiate the two species. Nor does there appear to 

 be a sac surrounding the atrium of the spermatheca, and possibly 

 derived from it, which contains the ovaries, as in the form which 

 I name here StiMmannia inermis. 



Michaelsen's species represents the last term in the series of 

 species of StiMmannia in which asymmetry is developed. 



Metschaina tanganyikae, sp. n. 



I feel obliged to form a new species for some specimens of an 

 eai-thworm on account of various characters to which I shall I'efer 

 in the course of the following description. It seems to belong to 

 Michaelsen's recently instituted genus Metschaina. 



This species is much like the StiMmannia just described, and, 

 like that worm, was found in wet sand close to Lake Tanganyika. 

 Its dimensions are rather less than those of the largest Stuhl- 

 'niannia inermis, but quite as great as some individuals of the 

 latter species. It has, too, the same bluish colour. I have 

 examined this worm almost entirely by means of longitudinal 



* See Reddard, P. Z. S. 1901, vol. i. p. 354, fig. 87. 



t "Die Oligochaeten Nordost-Afrikas," Zool. JB. (Abth. f. Syst.) 1903, p. 467. 



