40 THE MICROSCOPE. 



sists of a heterogeneous group, some forms of which 

 may be the zoospores of algse, others the germs of 

 animalcules. The Monadina, which quite recently 

 have been regarded as the most minute living crea- 

 tures discovered, comprising several distinct genera 

 such as Monas, Euglena, Uvella, Syncrypta, Chlamydo- 

 monas, Bodo, and many more can no longer stand as 

 a family representing different mature animal forms. 



For obtaining microscopic objects from the pond, 

 stream, or ditch, all you want is a wide-mouthed bottle 

 or two, a bit of wire, a walking-stick, a lens, and a 

 canvas or strong muslin net. A cutting hook to screw 

 into the end of your walking-stick will be useful in 

 nipping off the stems of aquatic plants, which always 

 harbour many forms of animal life. Several kinds of 

 animalcules, wholly invisible to the unaided eye as 

 single objects, are discernible as groups ; among which 

 I may mention to you the green masses of Ophrydium 

 versatile, and various Vorticellce, which may be fre- 

 quently seen encircling submerged stems or other 

 bodies with a dirty-white flocculent mass. Ophrydium 

 versatile lives in societies of many thousands together, 

 in balls of a whitish jelly-like substance. The colour 

 of the animalcules is green, and this gives the colour 

 to the masses of jelly in which they live. The size of 

 these balls varies from that of a pea to that of a man's 

 fist. In form each individual is very like a Stentor, 

 especially when it is free for these little creatures 

 can leave the jelly-like ball, and swim treely in the 

 surrounding fluid but as long as an Ophrydium is an 

 inmate of the jelly ball, it possesses, at the hinder 

 end, a very long thread-like tail, much longer than 

 itself; this tail seems to anchor the animalcule securely 

 in the gelatinous substance. You may meet with 

 these balls in clear water in the spring and early sum- 

 mer months. 



