THE CRUSTACEA OF NEW JERSEY. 171 



Key to tJic faniilics. 



a. First antennae not shorter than second ; mandibles with palps. 



b. Body more or less depressed, with posterior divisions poorly de- 

 veloped. COROPHIID.lv 

 bb. Body slender, more or less compressed, with posterior divisions nor- 

 mally developed. 

 c. Cephalon not produced in front. 



d. Perasopods without dactyls, but peculiarly modified for dig- 

 ging. PONTOPJRElID.iJ 

 dd. Perseopods with dactyls, not peculiarly modified. 



c. Rami of last pair of uropoda more or less foliaceous. 



GAMMARID.S; 



cc. Rami of last pair of uropoda more or less conspicuously 

 hooked. podocerid.e 



cc. Cephalon produced in front to a deflexed rostrum. iphimedid.s; 

 aa. First anttnnje shorter than second ; mandibles without palps. 



ORCHESTIID-E 



Family COROPHIID.^. 



Body smooth, depressed, metasome and urosonie compara- 

 tively poorly developed. Coxal plates very small, non-con- 

 tiguous. Cephalon broad, more or less produced in front, lateral 

 lobes small and narrow. Eyes, when present, placed within 

 lateral lobes of encephalon. Antennae more or less slender, in- 

 ferior ones usually more strongly built than superior, and ac- 

 cessory appendage of latter either present or wanting. Mandi- 

 bular, palps well developed and triarticulate, or comparatively 

 small with smaller number of joints. Oral parts otherwise nor- 

 mal. Gnathopoda of different structure in various genera, gen- 

 erally rather unecjually developed. Perseopoda short and stout 

 or very much elongated. Last pair of uropoda small, uniramous. 

 Telson usually lamellar and entire. 



Genera in moderate number. They are generally distinguished 

 by their depressed body and poor development of posterior 

 regions. 



Key to the genera. 



a. First two pairs of perccopods with spinning-glands. 



b. Mandibular palp three-jointed. cerapus 



bb. Mandibular palp two-jointed. corophium 



aa. First two pairs of peraeopods without spinning-glands. uNCiotA 



