88 HICK : KLEIN ON THE GENUS VOLVOX. 



met with either species in the pools and turf waters of the more 

 elevated regions of the Black Forest, i.e., at a height ranging from 

 900 to 1,300 metres. 



My own experience of the British species, though limited, is 

 in accordance with this. The localities in which my captures of 

 Volvox have been most abundant are : — Rawclifife near Goole, 

 Askham Bog near York, pools in the neighbourhood of Wetherby, 

 and — if I mistake not — Strensall Common — all low-lying and in the 

 region of the plains. On the south side of Manchester, where I am 

 now located, similar physical conditions prevail, and Volvox is of 

 common occurrence. 



The well-being of Volvox is of necessity affected by the plants 

 and animals associated with it. The statement has been made that 

 it thrives in company with Lemna, but Klein was not able to confirm 

 this. He found it diminish in quantity as the Lemna increased, and 

 the development was most abundant in pools where Lemna was 

 absent, although Sphagnum^ Vaiuheria, Conferva, Callitriche, Alisma, 

 and even Eqtdsetum limosuin, Utn'cnlaria, and Chara were present. 

 With him it flourished best along with such filamentous Algae as 

 Conferva, Mesocarpus, and CEdogoniiim, and with only a few aquatic 

 animals. Among the latter are several which feed on Volvox, and 

 if these are present it speedily disappears. Small crustaceans, he 

 says, are particularly destructive ; but in addition to these he points 

 to young Miller's Thumbs, and probably pond snails, as enemies of 

 Volvox. Elodea canadensis, like Lemna, seems to be adverse to the 

 well-being of Volvox when abundant, probably because it, too, pre- 

 vents the access of light on which Volvox is so dependent. 



Warm sunny days were found favourable to the development of 

 Volvox, while continued wet caused it to disappear almost entirely. 

 Here again my experience accords with this, and suggests further 

 that wind unfavourably affects Volvox, either directly or indirecdy. 



Specific Distinctions. — Into the confusion which has hitherto 

 prevailed on the question of specific distinctions, Klein has intro- 

 duced something like law and order, and it is now possible to 

 formulate with some precision the characters of two species of 

 Volvox. 



Looking back in the light of the results he has obtained by his 

 own researches, he finds that the form described by Leeuwenhoek 

 was the true Volvox globator, while the Volvox globator of Linnaeus 

 was a collective species. Ehrenberg accepted this name and gave it 

 a legitimate position by his careful descriptions and figures. Under 

 it, however, he appears to have confounded the vegetative colonies 

 of two species, and he accorded it an asexual mode of repro- 



