ENTOMOSTKACA. 367 



The PHYLLOPODA (from pAuUon, a leaf, tmdpous, foot), 

 have long and more or less shrimp-like bodies, with nu- 

 merous leaf-like appendages which serve both for loco- 

 motive organs and gills. They are found in both fresh and 

 salt water. One genus (Artemid) is found in salt-vats at 

 salt works ; and it abounds in Great Salt Lake, Utah, 

 the water literally swarming with them in some places. 

 Branchipus abounds in ponds, and is rather long and 

 slender. Limnadia has a bivalve shell, and thus external- 

 ly resembles Daphnia and Cypris. Nebalia reminds some 

 naturalists of the Decapods, while others (see p. 355) are 

 inclined to regard the genus as belonging to a distinct order. 



The CLADOCERA (Water-fleas or Daphnia, etc.), like the 

 Phyllopods, are without branchiae, but like the latter have 

 their thoracic members so formed as to serve the pur- 

 pose of respiratory organs. In most cases their eyes are 

 merged together so as to make them appear as one-eyed ; 

 and their cephal thorax is covered by a bivalve shell. 

 The name is from the Gr. klados, a branch, and keras, a 

 horn . 



The COPEPODA from the Greek hope, an oar, and 

 pous, a foot are very small or minute species, of a form 

 reminding us somewhat of shrimps and crabs. Cyclops 

 is only about one-sixteenth of an inch in length, and has 



FIG. 501. 



I 1 



Lerneonema radiata, Steenstrup and Lutken. 



apparently only one eye (Fig. 500, A and 1). Caligus and 

 Aryulus are parasitic on fishes ; the latter upon fresh- w a- 



