124 



THE GUIDE TO NATURE 



YAID 

 THE LENS 



Interesting Microscopic Animals. 



That the waters of the earth contain 

 a greater number of individuals, a 

 greater variety of forms, a greater ag- 

 gregation of peculiar creatures adapted 

 to their special environment, than ex- 

 ists on the land, is well known to 

 scientific men, but forgotten or per- 

 haps unknown to the majority of read- 

 ers that have little or no interest in- 

 scientific matters. In the fresh waters 



varying with conditions of tempera- 

 ture, abundance of food supply, and 

 perhaps of other essentials. 



Many, probably the greater number, 

 are entirely free-swimming. They are 

 independent ; they act as they please, 

 Mr as nature directed when they were 

 created. Others are permanently at- 

 tached, either immediately to the sup- 

 port, or through the intermediary of a 

 stem, that may be a simple trunk, 



THE EPISTYLIS. 



Photomicrograph of part of specimen on mount from Powers & Powers. 



of the United States alone, there are 

 more than two thousand known 

 species of Infusoria, or of what the 

 reader probably knows by reputation 

 as "animalcules." The drinking water 

 supplied by the city in which the writ- 

 er lives averages about five of these 

 "animalcules" to the drop, the number 



rigid and immovable, or that may have 

 a central, muscular thread that 

 promptly draws the animal away from 

 danger ; or the stem may be branched, 

 with an uninterrupted muscle extend- 

 ing through both stem and branches ; 

 or it may be branched, and have a mus- 

 cular thread interrupted at the fork of 



