312 REPORT OF NEW JERSEY STATE MUSEUM. 



genital openings mostly always in articular membrane between 

 sternum and coxa of fifth pair of thoracic legs. Branchiae as 

 dendrobranchise or phyllobranchise, only occasionally (Steno- 

 pidea) resembling trichobranchise. 



Key to the Super-Families. 



a. Mandibular palp large, foliaceous. pen.^idea. 



aa. Mandibular palp not large or foliaceous. caridEA. 



Super-Family PEN^IDEA. 



The Edible Prawns. 



Pleura of first abdominal somite overlap those of second. 

 Incisor portion of mandibles separated from molar portion by 

 groove. Endopodite (palp) of mandibles commonly very large 

 and foliaceous or subfoliaceus. Coxopodite of second maxillae 

 cleft in two lobes, distal of which promiinent and small proximal 

 receding. Endopodite of first maxillipeds long and sometimes 

 five-jointed. Last joint of second maxillipeds a distinct dac- 

 tylus, articulating end-on with distal end of propodite. External 

 maxillipeds distinctly seven-jointed. Third pair of thoracic legs 

 chelate, often first and second pairs also. Endopodites of ab- 

 dominal appendages from second to fifth without internal ap- 

 pendix at bases, except in second pair of male. Branchiae as 

 dendrobranchiae. 



■ Family PEN^ID^. 



The Edible Prawns. 



Rostrum usually well developed, laterally compressed. Oph- 

 thalmic somite little exposed. B^sal joint of antennular peduncle 

 dorsally concave for eye and strengthened at base on outer side 

 by spine-like scale. Antennular flagella two. Antennal scale 

 broadly foliaceus. First three pairs of thoracic legs chelate, 

 fourth and fifth pairs well developed. Exopodites present on 

 some or all thoracic legs, or entirely absent. Epipodite of second 

 maxillipeds large. Branchiae numerous. 



