SOME AQUATIC WORMS, ETC. 175 



soma, by placing a little piece of the moss in a watch- 

 glass with a small quantity of water, and gently tear- 

 ing away the leaves with needles, when the concealed 

 worms hurried out and were readily -captured with the 

 dipping-tube. If the watch-crystal stands on black 

 paper this 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 Ch<z- 

 tonotus and the Chironomus larva (Figs. 133, 134), both 

 having somewhat worm-like bodies. They are here 

 referred to for the convenience of both reader and 

 writer. The beginner will be sure at first to mistake 

 Chironomus larva for a worm. 



The bodies of all the aquatic worms are soft and easily 

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

 a cell shallow enough somewhat to restrain their move- ■ 

 ments when the cover-class is added, but deep enough 

 to avoid undue pressure or they will rapidly go to 

 pieces. 



The following Key will assist the beginner in deter- 

 mining to which class his worm or worm-like creature 

 may belong, leading to the flames 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, brown- 

 ish-red. Chironomus larva, I. 



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



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

 part of the lower or ventral flat surface; back 



