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Sample 10. Lake Victoria Nyanza. The sample was taken in 

 the 'Kavirondo Bay, in the vicinity of the town 

 Kisnmu (June, 1914). 



All the samples from Victoria Nyanza were taken in the 

 pelagic zone. 



The following forms of Cladocera were discovered in the 

 samples named above. 



Diaphanosoma excisum G. 0. S. resembles more closely its 

 variety longimanus Ekm. amongst the specimens of which 

 are fonnd transitory forms to the typical D. excisum, on 

 account of the length of the 2-nd pair of antennae. The 

 number and arrangement of denticles on the postero-inferior 

 angle of the valves is variable (fig. 1). 



Simocephalus serridatus Koch. In sample No. 1 were found 

 females with the ephippium, as well as males. 



Ceriodaphnia coniuta G. 0. S. The cephalic spine is single 

 (fig. 2), not double, although it is analogous to the spine 

 of Scapholebris mucronata. No transitory forms between 

 C. cor7iuta and Cer. rigaudi Rich, were discovered. The val- 

 ves do not diverge in the postero-dorsal angle, but there are 

 two spines (fig. 5) which were by some authors taken for 

 the free edges of the valves. Sometimes these spines are 

 absent. 



Ceriodaphnia rigaudi Rich. Disagreements of authors in 

 the description of this species are caused by the fact that it 

 is found in several varieties. Some of the morphological cha- 

 racters in the specimens investigated by me proved to be 

 constant. Such are: 1) the frontal spine; 2) the form and 

 structure of cauda; 3) the number of denticles on the dorsal 

 edge of Cauda; 4) the denticles on the fornix. Other characters 

 are variable, as, e. g. the measurements of the eye, the fron- 

 tal spine, the height of the head, the absolute size of the 

 body, the ratio between the length of the body and its width. 



Ceriodaplmia quadrangida v. liamata G. 0. S. differs from 

 the European species by a more obtuse postero-dorsal angle 

 of valves and several double spines on the dorsal margin of 

 the Cauda. 



Ceriodaplmia laticaudata P. E. M. The specimens investi- 

 gated by me differed from the European ones by the less 

 elongated head. The reticulation of the head is badly 

 expressed. 



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