12S PLANARIA VELOX. 



gion. Is it because such an infinity of the 

 insects with which the universe teems must 

 first have an aquatic abode, preparatory to 

 the perfection of all their organs ? or be- 

 cause the abundance of decaying matter, 

 wliose maceration is promoted by humidity, 

 affords an uninterrupted nutritious supply? 

 or, finally, because the receptacles being 

 fewer, the aggregate is greater in propor- 

 tion ? 



Towards the latter end of September 

 1812, several capacious vessels were filled 

 with water from a marsh situated in the 

 centre of a cultivated district. As the con- 

 tents subsided, uncommon variety of ani- 

 mals appeared. Numerous aquatic insects 

 complete, or larvae advancing to their suc- 

 cessive metamorphoses, performed their 

 agile evolutions, or sluggishly dragged their 

 members along. Beautiful hydrachnse, 

 decked in velvet colours, were ardently oc- 

 cupied in the pursuit of prey ; many de- 

 fenceless beings sought shelter amidst the 

 weeds and slime ; and myriads of minute 



