114 REPORT OF NEW JERSEY STATE MUSEUM. 



blunt, rounded, irregular, forming jagged sinuate edge. Frontal 

 plates narrow, scarcely prominent, not covering more than half 

 basal joints of first antennae. Eyes not evident in adult, visible 

 in young, placed one-third of space from: front edge and close 

 together. Second segment with paired dorsal plates broadly 

 elliptical to oval, one-half longer than wide, well inclined from 

 median axis, inner edges nearly straight to concave, widely 

 separated, hardly touch second pair and extend back to center of 

 lateral edges of third pair. Impaired median plate of second 

 segment wide, short, with straight entire hind edge. Third seg- 

 ment with small dorsal plates, almost circular, separated by deep 

 sinus, slightly enlarged at base. From wide separation of first 

 plates second pair entirely visible as seen above. Fourth seg- 

 ment with dorsal plates well enlarged, broader than genital seg- 

 ment and covering front third or two-fifths, well fused with 

 only wide and very shallow posterior sinus. Genital segment 

 elliptical, one-fifth longer than wide, hind lobes broad, evenly 

 rounded, with shallow median sinus. Sixth sfegment plate small, 

 its edge forms four-fifths of circle, rest narrowed into an an- 

 terior stem or neck where joining genital segment. It projects 

 behind lobes of genital segment for half or two-thirds its length. 

 Anal laminae rather narrow, slender, long as sixth segment plate, 

 acute at tips, and armed with two or three small spines irregu- 

 larly on inner edge, wings entirely absent in adult. Ventral 

 plate of abdomien much wider than sixth segment plate, its hind 

 edge usually evenly rounded. First maxillipeds slender. Second 

 maxillipeds much swollen, armed with pair of knobs acting like 

 forceps, knobs oblong. Basal joints of swimming-legs increase in 

 size from in front backward, all biramose with two-jointed rami, 

 but joints of fourth pair thoroughly fused and jointing only 

 indicated by marginal notches. Color in life said to be light 

 yellowish-white, turning- largely light straw-brown in alcohol. 

 These latter sometimes show a large deep brown to dusky blotch 

 on each side of carapace in front, followed by several others less 

 distinct on outer lateral regions, and often another also paler on 

 genital segment medianly above. Length 8 mm. 



Male. — ^Carapace orbicular, wider than long, with lateral mar- 

 gin evenly rounded. Posterior lobes broadly triangular, curved 



