126 CRUSTACEA. 



Sub-Order I. LOPHYROPODA. 



Body divided into distinct rings ; cara- 

 pace a buckler inclosing head and thorax ; 

 feet five pairs, mostly fit for swimming ; 

 ovary external Copepoda. 



Body wholly inclosed in a bivalve cara- 

 pace ; feet two or three pairs, fit for 

 walking ; no external ovary Ostracoda. 



TRIBE I. COPEPODA. 



Head and thorax consolidated and indistin- 

 guishable : 



Foot-jaws four pairs ; feet four 

 pairs Notodelphida. 



Foot-jaws two pairs; feet five 

 pairs Cyclopidte. 



Head and thorax firmly articulated, but distinct: 



One eye ; last pair of feet diverse 

 from the rest Diaptomida. 



Two eyes ; all the feet alike . . Cetochilidte. 



FAMILY I. NOTODELPHID^E. 



Notodelphys (Allm.). One eye; head consoli- 

 dated with thorax ; thorax and abdomen each of 

 four rings ; superior antennae many jointed, inferior 

 antennae prehensile; foot-jaws four pairs; ovary 

 within the body. Parasitic in the sac of Ascidia. 

 K ascidicola. Fig. 210 ; mag. 



FAMILY II. CYCLOPID^E. 



Canthocamptus (Westwood). Foot-jaws small, 

 simple ; antennae simple ; ovary single. 



