ii8 West: Phytoplankton of English Lake District. 



occurrence. The most noticeable of the latter were Cosmarmm 

 ahbreviatum var. planctonicum , Xanthidium antilopceum var. 

 depauperaium, Staurastrum furcigeruni forma eustephana, a 

 form of St. anatinum, St. Arctiscon, and Spondylosium pulchrum 

 var. planum. A few of the larger Entomostraca were present, 

 and also a few Rotifers, of which Notholca longispina and 

 Polyarthra platyptera were the most frequent, the latter occur- 

 ring in considerable quantity. 



3. Ennerdale Water, Cumberland. May 1903. Altit. 369 

 feet. Two and a half miles in length by three-quarters of a mile 

 broad. Average depth about 62 feet ; maximum depth 148 

 feet. The lake has a somewhat desolate situation, and only 

 two or three houses are near it. It is the most western of the 

 lakes, and lies between mountains which rise on each side to 

 2000 feet. It has a separate drainage basin, not being connected 

 with any of the other lakes of this area, and the valley above it 

 is strewn with numerous moraines. The plankton was domin- 

 ated by Peridinmm Willei, and numerous Desmids. Ceratium 

 hirundinella was also common. The smaller species of Desmids 

 were very abundant, the most conspicuous being Gonatozygon 

 monotcBnium , Staurastrum lunatum var. planctonicum, St. 

 defectum, St. curvatum,St. jaculiferum, Arthrodesmus triangularis, 

 Cosmarium suharctoum, and C. bioculatum. The most interest- 

 ing of the larger Desmids were Cylindrocystis diplospora var. 

 major, Micrasterias Sol, M. pinnatifida, Cosmarium connatum, 

 Staurastrum furcigerum, St. Arctiscon, St. longispimim, and 

 St. sexangulare. The Entomostraca were very numerous, and 

 included various Copepods, Bosmina longirostris, and an abun- 

 dance of Nauplii. Many of the dead individuals had been 

 attacked by species of Saprolegnia. Only a few Rotifers were 

 present, the two most conspicuous being Anurcea cochlearis and 

 Notholca longispina. 



A few specimens were observed of a solitary species of the 

 genus Dinobryon which we have described as new under the 

 name of D. crenulatum. 



4. Derwent Water, Cumberland. June 1903. Altit. 238 

 feet. About three miles in length by a little over a mile in 

 breadth. Average depth about 18 feet ; maximum depth 72 

 feet. This lake receives the drainage of the Borrowdale moun- 

 tains, and although the small town of Keswick is not far from 

 its northern shore, there is probably little contamination from 



Naturalist, 



1 



