584 DR. W. A. CUxYNlNGTON Ox\ THE 



recorclerl from the same locality as S. stuhhnanni. Nothing 

 further is known of this form. 



Examples of two species of Stenostoma from Bukoba were 

 among- the material examine 1 by Bohmig, bat their unfavourable 

 state of preservation did not permit of nearer identification. 



5. Gyrator hermaphroclitus. 



A pelagic Tarbellarian collected in Victoria Nyanza is identified 

 with this species by Bohmig. It is well known in Europe. 



6. Vortex quadridens. 



This typo is established merely on the evidence of sketches and 

 notes by Stuhlmann. It is admitted that certain important 

 features of the genital apparatus are unknown. Obtained from 

 stagnant water at Bukoba. 



From the above it will be observed that Turbellaria are only 

 recorded at present from Lakes Victoria and Tanganyika. From 

 Victoria Nyanza and its neighbourhood five forms have been 

 specifically identified, three of them being peculiar to the lake. 

 There are, in addition, two types which are unnamed. These 

 records of Bohmig, however, need confirmation, as they are based 

 on very meagre evidence. From Tanganyika a single endemic 

 species is known, which belongs to the widely distributed genus 

 Flcm%riob *. No doubt farther representatives of this group will 

 eventually be found in the great lakes, but they appear to be less 

 common than might have been expected. There is no suggestion 

 of a striking Tarbellarian fauna in Tanganyika and little indica- 

 tion that fefuch will be discovered in the future. 



Trbmatoda. 



Practically nothing is known of the distribution of these 

 exclusively parasitic animals in the lakes of Africa. Following 

 the argument a,dvanced in the section dealing with the Nematoda, 

 it seems only logical to include such forms in a lake fauna. In 

 the case of these organisms they may be obtained in the free- 

 swimming larval stage, or infesting an intermediate MoUuscan 

 host or in their final vertebrate host. As far as I am aware, the 

 description given by Daday (76, p. 39) of two Oercaria larvae from 

 the neighbourhood of Nyasa is the only account which concerns 

 any of the lakes. Both were found in material from ponds near 

 Nyasa and were described as new larvte, though it seems doubtful 

 whether such determinations have much systematic value. They 

 have received the names of " Cercaria'' schizocerca and " Cercar'ia^^ 

 hoplophora 76, p. 288). 



* It seems clear tliat Stulihnaiui's statement that Plauavians cannot survive 

 temperatures of over 25° C. (185, p. 319) is not universally true. The specimens I 

 collected in Tanj;anyika were taken in quite shallow water, where the temperature 

 tends to be liigliast, yet mj' thei'mo'.neter readings for the surface of the lake showed 

 a hiiiher average than 25'^, 



