512 BULLETIN 54, UNITED STATES NATIONAL MUSEUM. 



"Male: Body long and slender, divided into fourteen segments. 

 Head subrotund. Internal antennae short and robust, 3-jointed; 



joints spinous. External 

 antennae long, 7-jointed; the 

 first two joints spinous, the 

 others bristled. First joint 

 of the thorax transversely 

 oblong, the remainder de- 

 pressed, pyriform in out- 

 line. Feet in seven pairs, 

 the ante-penultimate joint 

 spinous, the penultimate 

 joint broad and with the 

 claw recurved. Abdomi- 

 nal segments depressed, 

 pyriform in outline, each 

 provided with a pair of 

 peculiar ventral append- 

 ages, and, except the fifth 

 one, with a lateral irregu- 

 lar pigment cell. Caudal 

 segment round, with a 

 pair of divergent append- 

 ages. Length of female 

 four lines, breadth three 

 lines; length of male one 

 and a quarter lines. "- 

 LEIDT." 



FIG. 560. LEIDYA DISTORTA (AFTER LEIDY). a, DORSAL 

 VIEW OF MALE, b, ABDOMINAL SEGMENTS OF MALE WITH 

 PECULIAR APPENDAGES. C, RIGHT LEG OF MALE. d, 

 HEAD OF MALE WITH ANTENNA. ALL MAGNIFIED. 



84. Genus GRAPSICEPON Giard and Bonnier. 



Female with two median dorsal tubercles, one on the sixth and the 

 other on the seventh thoracic segment. 



Five anterior segments of abdomen with the lateral parts or pleural 

 lamellae produced into long, tapering prolongations, which are digi- 

 tate. Abdomen distinctly segmented. Pleopoda in five pairs, well 

 developed, double-branched; outer branches similar to the pleural 

 lamellae of the segments; inner branches in the form of large tubercles. 



Uropoda consisting of two elongate lamellae similar to the outer 

 branches of the pleopoda or the pleural lamellae of the abdominal 

 segments. 



Male with all the segments of the thorax and abdomen distinct. 

 There are five pairs of rudimentary pleopods. The uropoda are rep- 

 resented by two bunches of stiff hairs. 



Branchial parasites. 



Journ. Acad. Nat. Sci. Phila. (2), III, 1855, p. 150, pi. xi, figs. 26-32, 



