SOME AQUATIC WORMS, ETC. 165 



away the leaves with needles, when the concealed worms 

 hurried out and were readily captured with the dip- 

 ping-tube. If the watch-crystal stands on black paper 

 the work is facilitated, as the translucent worms then 

 appear to the naked eye as minute, writhing, silvery 

 threads. 



In this chapter the reader will also find descriptions 

 of two very common microscopic aquatic animals, one 

 of which is certainly not a worm, the proper position of 

 the other being rather doubtful. They are Chcetonotus 

 and Chironomus larva (Figs. 131, 132), both having some- 

 what worm-like bodies. They are here referred to for 

 the convenience of both reader and writer. The begin- 

 ner will be quite sure to at first mistake Chironomus 

 larva for a worm. 



The bodies of all the worms are very soft and easily 

 injured. It is best, therefore, in studying them to use 

 a cell shallow enough to somewhat restrain their move- 

 ments, when the cover-glass is added, but deep enough to 

 avoid undue pressure, or they w r ill rapidly go to pieces. 



The following Key will assist the beginner in deter- 

 mining to which class his worm may belong, leading to 

 the names of the groups under which some of their 

 generic titles may be found : 



1. Body with four leg-like appendages bearing hooked 



bristles ; eyes distinct ; head large, brownish - red. 

 Chironomus larva, I. 



2. Body without leg-like appendages (a). 



a. Tail forked ; mouth small, circular, on the front 



