THE CRUSTACEA OF NEW JERSEY. 107 



biramiose, rami of first three pairs two-jointed, of fourth pair 

 one-jointed and enlarged into flattened laminje with large fold of 

 skin on ventral surface. 



Male. — Fixed and degenerate, similar to female except genital 

 segment without dorsal plates but covered by those of fourth 

 segmient, which also reach nearly to end of abdomen. Latter 

 plumip, not flattened, twice wide as long-, without lateral lobes. 

 Anal laminae close together, armed with good sized setse. 

 Fourth legs but little enlarged, rami one-jointed, without ventral 

 fold of skin. Plumose setae on first three pairs of legs less* 

 rudimentary than in female. 



Cecrops latreillii Leach. 



Plate 27. 



Cerops latreillii Leach, Encyclop. Britan. Siippl. (Anniilosa) 1816, p. 405, 



PI. 20, figs, 1-5. No locality. 

 ■ Leidy, Proc. Acad. Nat. Sci. Phila., 1890, p. 282. Beach Haven, New 



Jersey (on Mola mola). 



Female. — Carapace oval, long as wide, with prominent frontal 

 margin and deep triangular posterior sinus. Frontal plates 

 almost entirely fused with carapace, separated by wide deep 

 median sinus. On lateral edges just behind frontal plates a 

 well-defined notch on either side in base of which first antennre 

 are attached. Another notch a little posterior on lateral mar- 

 gins formed by transverse groove separating cephalic from 

 thoracic portion of lateral areas. This groove far forward, thus 

 cephalic portion in front of it small and triangular, while thoracic 

 portion behind it nearly four times as large and trapezoidal. 

 Second and third thorax segments fused, with sing-le pair of 

 lobes and single pair of dorsal plates. Broad lateral lobes ap- 

 parently belong to second segment, reach well out beneath hind 

 lobes of carapace. Small dorsal plates belong to third segment 

 and overlap following segment a little. Fourth segment with 

 pair of medium-sized plates which reach about to center of those 

 on genital segment. Each small dorsal plate triangular with 

 well-rounded corners. Genital segment with dorsal plates en- 



