COLACTUM. 107 



a pointed tail ; the head and tail have no colour, 

 but the body is bright green, and the eye bril- 

 liant red ; it is a beautiful species, not only from 

 its bright colours, but from the elegance of its 

 form, and its mode of swimming; when sta- 

 tionary, it frequently changes its shape. There 

 are several other species, but those mentioned 

 are the most common : I have found them all in 

 pond-water. 



A little creature, attaching itself to other 

 bodies by a foot-stalk, and frequently found on 

 Eotatoria and the crustaceous creatures allied 

 to the water-flea, is called Colacium. I have 

 seen it covering the stalks of the Vorticella con- 

 vattaria, so as to give the whole the appearance of 

 a minute branch of green leaves. The species 



