148 CLAS3 CRUSTACEA. 



creases. They will not live in stagnant water containing 

 much decomposed vegetation, and require, therefore, to 

 be kept for observation in a large vessel of clean water. 

 They are easily caught after a shower of rain, on the 

 under surface of the duckweed, by taking out a little 

 with a basin or cloth net. When found, they appear 

 busily engaged in search of prey, moving about with 

 great activity, and examining every portion of the plant 

 in the most scrutinizing manner. In this pursuit the 

 body is not bent as in the magnified representation in 

 the engraving, but is kept in a straight crawling posi- 

 tion. Their natural length is about the three hundredth 

 part of an inch. 



The female of the last species has two outward recep- 

 tacles for the eggs ; in this there is but one, and 

 that is placed on the under part of the animal near the 

 tail. 



The Hairy Cypris, (Ct/pris pubera.) 



These singular little creatures are found in stagnant 

 fresh water: they are very small, and, at first sight, ap- 

 pear like a bivalve shell. The animal which is enclosed 

 in this two-valved case, opens and shuts it at will ; when 

 it does this, it throws out from one end of the shell nu- 

 merous whitish hair-like members ; it is by moving these 

 that it is enabled to swim with considerable celerity, and 

 it never stops until it meets with some object on which 

 it can rest. Its two antenna), which issue from the fore 

 part of the shell, are long, very flexible, and bent back- 

 wards ; their articulations are numerous, which gives 

 them great freedom of motion. The movements of these 

 antennoe contribute materially to the swimming powers 

 of the creature. 



