526 



ZOOLOGY 



SECT. 



There is considerable diversity of form among the Euphyllopoda. 

 Apus lias already been described. Branchipus (Fig. 413, 1) and 

 Artemia (the Brine-shrimp), are small shrimp-like forms, the 

 former living in fresh-water lakes, the latter in brine-pools ; they 

 have no carapace, and the eyes are raised on unjointed stalks. In 

 Liinnetis (2), on the other hand, the carapace is large enough to 

 cover the whole body, and in Estheria (3) it takes the form of a 

 dull, formed of two parts or valves, united by a hinge, and resem- 

 bling th<- shell of a cockle or other bivalved mollusc. The limbs 



. ant.l 



ant. 2 



ant. 2 

 h e r i a 



Vic.. 413. Three Euphyllopoda. In 3, a is the shell, l> the animal with one valve of the shell 

 rfiinived ; ant 1 , antennule ; nnt-. antenna; ht. heart; ///.adductor muscle; ntd. mandilik- ; 

 ov. [ovary a. unpaired process from head ; p, copulatoiy appendages ; sh.rjl. shell-gland; 

 /. testis. (After Gerstaecker.) 



have the same general structure as those of Apus, but the 

 :inteiin;e are often of considerable size, and are sometimes modified 

 into prehensile organs. 



In the Cfttdoccra, of which the common fresh-water Daphnia 

 (Fig. 414, I) is a good example, there is a great reduction in size 

 (1-2 mm.), and a corresponding shortening of the body, by a 

 reduction in the number of metameres. Segmentation is \er\ 

 imperfect, and the whole body is covered by a large folded 

 carapace. The abdomen is turned downwards and is inconstant 

 movement, sweeping out any foreign particles which may have 

 made their way among the feet. Between the abdomen of the 



