123 



THE PLANKTON FORMS. 



PHYTOPLAXKTOX. 



The pliytoplanktou -was made up of three forms, Chithrocystis, Coe- 

 losphaerium and Oscilhiria. Chithrocystis was much more abundant than 

 the other two forms as it made up about 75 per cent, of the total quan- 

 tity of phytoplanlvton. 



CRUSTACEA. 



Copepod a. —My thanks are due Prof. C. DAvight Marsh for his deter- 

 mination of the following copepods: 



EpiscJiura lacnstris Forbes. 



Diaptomus oregoncnsis Lillj. 



Diaptomns hirgei Marsh. 



Cyclops pulchelhis Koch. 



Cyclops hrevispinosits Herrick. 



Cyclops lenclcarti Sars. 



Cyclops alMdiis Jurine. 



Cyclops prasiniis Fischer. 



Cyclops seiritlatiis Fischer. 



Ergasilus. 

 The following concerning Diaptomus birgei is quoted from Professor 

 Marsh's letter: "The finding of D. birgei Is of great interest to me. I 

 described the species some j^ears ago from a few specimens from New 

 Lisbon, AVisconsin, and have never seen a specimen since. I had begun 

 to fear that I had described a freak form and that the species would not 

 stand; but here comes the creature in the proper proportions. It is a 

 little queer that I should have found it only in two such widely separated 

 localities, but doubtless it lives at some intermediate locations." 

 Cladocera. — The folloAving linmetic forms were found: 



Daphnia liyaliua Leyd. 



Daphnia piilex De G. var. puliearUi Forbes. 



Daphnia retrocun-a Forbes. 



Diaplianosoma hrachyurum Sars. 



Ceriodaphnia lacnstris Birge. 



Leptodora liyalina Lillj. 



Chydorns. 



Bosinina, 



