CYCLIDIUM. 115 



Cyclidma contains animalcules having no lorica 

 and no eyes ; bristles, or cilia, are the organs 

 used in locomotion. The genus Cydidium has a 

 compressed body, and the cilia are placed in a 

 single circular row. C. glaucoma is abundant 

 in the spring, and may be known by its oblong 

 body, the ring of cilia, and its peculiar move- 

 ment, which is generally quick ; but frequently 

 the little creature stops, and then springs sud- 

 denly to another spot, with a light, graceful mo- 

 tion. The family Peridin&a possesses a lorica, 

 and probably eyes, and the cilia are in the form 

 of a crown. Some of the genera have a deli- 

 cate proboscis, in addition to the cilia ; they are, 

 however, insignificant in size, and I shall pass 

 them over, to give more space to the next family. 



