VI 



and fresh-ioater shelhj from the comparative 

 facility/ with which the subjects may be collected 

 in their living state. 



How far unlooked for casualties may some- 

 times befriend the researches of the Naturalist, 

 the following circumstance ivill elucidate. 



A few summers since, I had collected some 

 stagnant loater, for the purpose of examining 

 the infusorial tribe ; and over the head of the 

 vessel containing this water loas placed a piece 

 of fine gauze. Some time afterwards, upon 

 looking into the vessel, I ivas surprised to see the 

 surface of the ivater, and the under side of the 

 gauze strewed ivith minute winged insects, chiefly 

 of the Neuropterous tribe. Is it not therefore 

 probable, that the infusorial order ofivorms may 

 be merely the minuter species of Ephemercd in 

 their mediate stages of transformation? Of the 

 natural aconomy of this last tribe we know only, 

 that the egg is dropped into water, and that it 

 emerges in a perfect ivinged state. The larva 

 and chrysalis metamorphosis must take place 

 under water, and for this purpose they must be 



