174 



BULLETIN: MUSEUM OF COMPAKATIVE ZOOLOGY. 



and rr "very rare" (only a single or few individuals seen). With re- 

 gard to the frequency the above mentioned cii'cu instance, that the silk 

 gauze used was relatively wide-meshed, must be remembered. 



PHYTOPLANKTON FROM VICTORIA NYANZA, 

 Pebkuauy, 1908. 



The prominent forms are the Diatoms of which again one species is domi- 

 nant, viz., Melosira Agassizii, sp. nov. ; this species which is closely related 

 to M. granulata occurs also in the plankton in April (recorded by G. S. 

 West, I. c, p. 147, aa il/. granulata) and in November (recorded by me, 

 I. c, p. 338, as M. off. granulafa), but is both in April and November less 

 abundant than M. nyassensis., while in February M. Agassizii is more 



