430 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.38. 



A 38. Terminal segmenl of second leg enormously lengthened. First legs partly 

 prehensile. First antenna five-segmented. One ovisac. Muddy bottoms. 



6 to 30 fathoms Longipedia. 



Terminal segment of second leg unusually lengthened. First antenna six- to 



nine-segmented \ : '>'- 1 . 



A 39. Basal segmenl of inner ramus of first leg enormously broadened. First leg 



otherwise modified A 40. 



Basal segmenl of inner ramus of first leg not enormously broadened. First leg 



normal A 13 



A 40. Posterior part of body not so sharply demarcated from the anterior pari as to 

 approximately equal width of the abdomen. Body much depressed. Basal 

 segment of inner rami of first leg very broad and triangular, and as long as 

 (lie outer ramus. One egg sac. 6 to 20 fathoms, adhering to debris, etc. 



I'/omene. 



Posterior part of body sharply and abruptly demarcated from the anterior part, 

 with abdomen approximately one-third width of segment just anterior to it. 

 Body more or less depressed. First antenna eight- to nine-segmented. One 

 egg sac ^ l ' ■ 



A 41. .Middle segmenl of inner ramus of third and fourth legs, with two seta' each. 



Anterior pari of body broad. Sublittoral, closely clinging to fronds of a!, a . 

 as 1. a in in, inn Psamath . 



Middle segmenl of inner ramus of third and fourth legs, with one seta each.A 42. 



A42. Middle segmenl of outer ramus armed with a strong, claw-like spine curving 



outward. Littoral, amongsl algse Machairopus. 



Middle segmenl of outer ramus nol armed with a strong, (daw-like spine curving 

 outward. Fifth legs long and narrow. The two segments preceding genital 

 segment, fornicate posteriorly. Sublittoral. closely clinging to fronds of 



Laminaria Vspidiscux. 



A 13. Caudal rami, long, narrow, linear, and so contiguous as to almosl appear as a 

 single appendage. Genital segmenl in female produced on each side to a 

 recurved, spinifonn projection. First antenna six-segmented, with a long 

 fusiform appendage from the fourth segment. One egg sac Male unknown. 

 Creat depths, loose muddy deposits < 'ervinwpm. 



( audal rami, not long, narrow, and so contiguous as to appear as a single appen- 

 dage \ 1 1 



A II. Both rami of lirsi legs natatory, as those of the natatory legB, nol prehensile. 



< ) I1( . egg sac A 45. 



Both rami of lirst legs not natatory, one or both prehensile. One or two egg 



- \ ,s 



A 15. Basal segmenl of first leg with three large accessory spines, em' of which is 



situated on the 'face of the segment, the others on the margins. Abdomen 



distinctly separated from the thorax. Inner branch of second antenna two- 



mented Inner ramus second legs modified in male. 20 to 30 fathoms, 



muddy bottom Robertsonia. 



Basal segmenl of firsl leg normal, with no accessory spines A 46. 



A in. Anterior pari of body not appreciably broader than the posterior part. Body 

 very slender, linear The two middle setse of the furca greatly elongate. 



< >uter branch of second antenna greatlj elongate. Pelagic, near the surface, 

 in plankton MicrosetelUi. 



Anterior pari of bodj appreciabrj broader than the posterior part A 47. 



