Entomostraca of Lake Basse nthwaite. 471 



Brief Statement of recorded Distribution in Britain of the 

 Species taken in Lake Bassenthwaite. 



ENTOMOSTRACA. 

 Cladocera. 



Bosmina longirostrts, Baivd. 



Bosmina tonf/irostris, Baird, British Eutomostraca, p. 105, tab. xv. 

 fig. iii. 



This species appears to be fairly common and widely 

 distributed in Britain. In Bassenthwaite it was very common 

 in all the tow-nettings in April, but rare in June. 



' Sida crystallina^ Straus. 



Sida crystallina, Baird, Brit. Entom. p. 107. 



Baird remarks that this species is of rare occurrence, but 

 Scott records it as being common in Raith Lake in Scotland. 

 It was the most common species taken in April 1898. In June 

 very few specimens were taken, but these were of a large 

 size, with well-developed ova and embryos. 



Chydorus spJicericus, Baird. 



Chydorus sphcsricus, Baird, Brit. Entom. p. 126, tab. xvi. tig. 8. 



Common in ponds and ditches in Britain almost all the 

 year round. 



Leptodora hyalina, Lilljeborg. 



Leptodora hyalina, Broun, Klass. und Ordn. des Thier., Arthrop. 

 Crust., Erste Hiilfte, Tafeln, Taf, xxi. fig. 1. 



This species was first taken in England by Bolton * from 

 the Olton reservoir, near Birmingham. Later it was taken 

 by Beck in Lake Grasmere. Scott has taken it in the 

 Scottish lakes (Loch Leven, Loch Morar), and remarks that 

 while it is considered to be a rare species, it is not very rare 

 in Loch Leven. 



In April only the larvaj and very young forms were taken, 

 chiefly at the surface, in Bassenthwaite. In June this 

 species was exceedingly abundant, with eggs, embryos, and 

 young, but no young larvse were taken. It was, moreover, 

 confined to the middle of the lake, where the water is deep 



* Ann. & Mag. Nat. Hist. (6) vol. ix. p. 53. E. Ray Lankester, "On 

 new British. Cladocera discovered by Mr. Conrad Beck in Grasmere Lake, 

 Westmoreland." 



