222 



BULLETIN 15 8, UNITED STATES NATIONAL MUSEUM 



Female. — Cephalic segment about half of the metasome; rostrum 

 long, prominent, curved downward, and rounded at its tip, with a 

 minute hair on each lateral margin; urosome two-thirds as long as 

 metasome, without spinules; genital segment divided; caudal rami 

 quadrilateral, wider than long. First antennae 8-segmented, two 

 basal segments enlarged; exopod of first legs three-fourths as long 

 as basal endopod segment ; distal segment of third exopod with four 

 spines and four setae; distal segment of fifth legs large and foli- 

 aceous, as wide as long, with six setae, the third inner one filiform, 

 basal expansion triangular, scarcely reaching the center of the distal 

 segment, with five setae, the middle one larger and longer than the 

 others. Total length, 0.8-0.9 mm. 



Figure 149. — Amphiascus cinctus: a. Female, fifth leg; h, male, fifth and 

 sixth legs ; c, male, first leg ; d, male, second leg 



Male. — First antennae geniculate, with two long aesthetasks; sec- 

 ond basipod of first legs with a stout curved spine at the inner 

 corner, reaching beyond the center of the basal endopod segment; 

 second endopod nearly as long as exopod, with an apical spine, 

 curved abruptly at the center, and two outer spines, the proximal 

 one widened; distal segment of fifth leg oval, with six setae, the 

 third inner one filiform, basal expansion reaching the middle of the 

 distal segment with two apical setae ; rudiments of sixth legs present. 

 Total length, O.Y-0.8 mm. 



Reiimrks. — The deep pink transverse band on the metasome retains 

 its color in formalin and affords a ready means of identification. 

 The species has never before been reported from our coasts. Brian 

 published figures and descriptions of nauplius and metanauplius 

 stages in Studi del Laboratorio Marino Genova, 1921 (pp. 87-88). 



AMPHIASCUS SINUATUS Sars 



Figure 150 



Amphiascus sinuatus Sars, Crustacea of Norway, vol. 5, p. 178, pi. 118, 1906. 



Occurrence. — A few specimens of both sexes were obtained in two 



of the brackish ponds on Chappaquiddick Island, July, 1925, and in 



Cuttyhunk Harbor. 



