Freshwater Algae 33 a 



America, but not from North America, although a variety commune Hirn., 

 which is larger than the type, is known from Massachusetts, U.S.A. 



Vegetative cell diameters: constriction 14ju; wider part 23-25^1 ; 2^-3 times 

 diameter in length. 



Oogonia: 45 x 60ju. 



Oospore : none fully ripened. 



Antheridia: diameter 18^, length 5/i. 



Oedogonium paludosum (Hass.) Wittr. var. americanum Nordst. 



This species was slightly more plentiful than the last and occurred with 

 reproductive organs only in the swamp at Herschel island. It is a monoecious 

 species bearing single ellipsoid oogonia with a superior pore. Oospores were 

 not fully matm-ed and the details of the wall were rather obscure. Distinct 

 longitudinal lines were visible and were 18-24 in number. Antheridia were 

 1-5 celled, usually 3 celled. Neither the type nor variety are common in U.S.A., 

 nor have they been recorded from Canada or the arctic regions. 



Vegetative cell: 15-25/i diam., l|-8 diameters in length. 



Oogonia: 60-65m diam., 80-1 00^ long. 



Oospores: 45-50/1 diam., 74-90^1 long. 



Antheridial cell: 12-20/4 diam., 5-8/i long. 



Heteeokontae. 



BOTRYOCOCCACEAE. 



Botryococcus Kiitz. 



Botryococcus Braunii Kiitz. 



This alga is a typical plankton organism, although it is frequent in algal 

 collections apart from plankton. Fairly large masses were found in the plankton 

 and in tundra collections from Teller, and in the plankton of the big lake at 

 Bernard harboiu:, where it was also fairly abundant. It is common throughout 

 Eiurope and in the U.S.A. I have recently found it in Manitoba, although, at 

 present there is no published record for Canada. I cannot find any arctic record 

 for it. 



OPHIOCYTIACEAE. 



Ophiocytiutn Nag. 

 Ophiocytium tnajus Nag. 



This species is the largest of the genus and readily recognized. One end 

 of the cell is usually slightly swollen and capitate, and the other is attenuated 

 into a spine of varying length. It is not common in America and has not been 

 previously recorded from American arctic regions. It is fairly plentiful at 

 Teller, where it was found in the brackish pond as well as in fresh water. It 

 was also present in collections from Herschel island, and in the plankton of the 

 big lake at Bernard harbour. 



TRIBONEMACEAE. 

 Tribonema Derbes & Solier. 

 Tribonema bombycina (Ag.) Derb. & Sol. forma tenuis Hazen 



This, which is a small form of the species, is fairly common in most parts 



of the world, although not so common as the type; it is not infrequent in arctic 



regions. It occurred with other algae in a lagoon just west of Martin point, 



at Herschel island, and at Cape Bathurst. At no place was it very plentiful. 



49069—3 



