162 DROS OF WATER. 



and in water in which oak-leaves or bark has 

 been steeped. It is of an elegant spindle-form 

 when stretched out, the rotatory organs small, 

 the foot forked, and having also processes above ; 

 the body is very transparent, and the jaws can 

 be distinctly seen engaged in grinding down the 

 food. At first sight it greatly resembles the fol- 

 lowing genus, but the rotatory organs and want 

 of eyes distinguish it. 



Rotifer vulgaris (Drop IV. fig. 11). This in- 

 teresting animalcule was one of the earliest, dis- 

 covered by the aid of the microscope. It was 

 first described by Leeuwenhoek about 150 years 

 ago, and has never since ceased to be a favourite 

 with those possessing microscopes. It is easily 

 obtained in spring and summer, being abundant 



