448 BULLETIN 15 8, UN"ITED STATES NATIONAL MUSEUM 



Male. — Head fused with first segment, carapace with flat margins •, 

 free and genital segments fused, but without a dorsal plate. Abdo- 

 men 1-segmented and visible in dorsal view. Rami of first and sec- 

 ond legs like those of the female, of third and fourth legs fused or 

 separate, but always extending backward; fifth legs lacking. 



KEY TO THE SPECIES 



FEMALES 



1. Dorsal plate with a deep median posterior sinus, not covering 



abdomen; fifth legs present longipes, new species (p. 448) 



Dorsal plate without a posterior sinus, covering entire abdomen ; 

 no fifth legs 2 



2. Posterior portion of dorsal plate wider than anterior and folded 



around bases of fourth legs like a skirt paenulatus (p. 449) 



Posterior portion of dorsal plate same width as anterior and not 

 folded around fourth legs 3 



3. First antenna 8-segmented ; fourth legs narrow, sharply pointed ; 



third legs close together and parallel pomatomi (p. 450) 



First antenna 3-segmented ; fourth legs broad, bluntly pointed ; 



third legs widely separated and divergent brevzoortiae (p. 451) 



MALES 



1. Fourth legs biramose, endopod half as long as exopod, both rami 



acute paenulatus (p. 449) 



Fourth legs uniramose and cydindrical 2 



2. Fourth legs stout, acute, and widely divergent ; third legs also 



acute and one-third as long as fourth pair pomatomi (p. 450) 



Fourth legs nearly parallel and blunt ; third legs also blunt and 



half as long as fourth pair brevoortiae (p. 451) 



LERNANTHROPUS LONGIPES, ne^r species 



Plate 28 



Occv/rrence. — Four females with egg strings were found on the 

 gills of a black drum {Pogonias cromis) , caught within the present 

 area and placed in the New York Aquarium. One has been selected 

 as the species type, with U.S.N.M. No. 59788; the other three be- 

 come paratypes, with U.S.N.M. No. 59789. 



Color. — After remaining a short time in formalin the body was 

 cinnamon-brown, somewhat lighter on the ventral surface and in the 

 fourth legs. 



Female. — General form elongate and narrow, owing chiefly to the 

 great length of the fourth legs. Cephalothorax orbicular, as wide as 

 long, with lateral flaps concealing the antennae and mouth parts, 

 except in ventral view. Anterior portion of dorsal plate about as 

 wide as long, the parts representing the second and third segments 

 separated by distinct lateral invaginations and a much less distinct 

 dorsal groove. Posterior portion of dorsal plate orbicular, as wide as 

 long, with a median posterior sinus, one-fourth the length of the 



