no. 1758. OX MARINE COPEPODA IND CLADOCERA. SHARPE. 431 



A 47. Posterior antenna with the outer ramus | -ly developed, and occasionally of 



only two segments. Anterior pari of body slightly depressed and broadened. 

 Fifth legs large and alike in the sexes. 3 to 6 fathoms, muddy sand. 



Pst udobradya. 



Posterior antenna well developed and distinctly three-segmented. Anterior 

 part of body somewhal depressed and broadened. Fifth feel small (in male 

 but one-segmented, a small setiferous lamella). U) to 30 fathoms, sandy 



bottom Bradya. 



A 48. Rami of the natatory legs form a decided angle with the segment bearing them. 

 Body depressed, oval, shield-shaped. Rolls up when disturbed. (Miter 

 rami of first legs the larger. Fifth legs falciform, alike in the sexes. Furca 

 short, broad, and lamellar. Littoral, on Laminaria and other algae, and on 



sandy and gravelly bottoms, 2 to 20 fathoms 1//' ttthu. 



Rami of the natatory legs not forming a decided angle with the segmenl bearing 



them A 49. 



A 49. Outer rami of the first legs somewhat longer than the inner rami A 50. 



Outer rami of the first legs somewhat shorter than the inner rami, or occa- 

 sionally subequal. (Thalestris and Parathalestris variable) A 55. 



A 50. Middle segment of inner rami of fourth legs with no setae on inner margin, one 

 Beta in similar location of other natatory lo.u's. Inner rami of second legs 



modified in male: One egg sac. Rock and tidal } Is and occasionally in 



fresh water in-shore Tigriopus. 



Middle segment of inner rami with at least one seta. One egg sac A 51 . 



A 51. Body quite Hat and shield-like. No rostrum. Eye present. Middle segment 

 nf inner ramus of second legs modified in male. 6 to 20 fathoms, at sea. 



. 1 mi nnphia. 



Body not flat nor shield-shaped. Rostrum present A 52. 



A 52. Fifth legs of both sexe:- foliaceous, those of the female large, more or less covering 

 the egg sac \ •»:'.. 



Fifthlegs of female slender, oot covering the egg sacs. Male unknown. Genital 

 Begmenl of female with a well-developed dorsal suture (transverse), and pro- 

 duced mi each side to a strong spiniform projection. Furca somewhat lamel- 

 lar. Eye absent. First antenna with a very large seta on the fourth seg- 

 ment. 50 to <i() fathoms Eucanuella. 



A 5:5. Fifth legs of female enormously developed, foliaceous, wholly covering the 

 egg sacs. Genital segment in female with a well-marked dorsal transverse 

 suture, and not produced on each side to a strong spiniform projection. K\ e 

 large and complicated. Inner rami of second legsmodified in male. Among 

 algae, 6 to 20 fathoms Phyllothalestris. 



Fifth legs not enormouslj developed, and commonly nol covering the egg 



sacs .A 54. 



A 54. Rostrum sharply defined from the cephalic shield, and partially mobile. 

 Body slender, cylindrical, and somewhat laterally compressed, fifth legs of 

 moderate size. Littoral and tidal pools, among algae Parathalestris. 



Rostrum not defined at base, short, thick, and immobile. Bodyrobust. Kami 

 of first legs Bubequal in length. Fifth legs large. Littoral, L0 to 20 fathoms, 



in algae Thah stris. 



A 55. Inner margins <<i middle segments of inner rami of the natatorj legs with 2 seta' 



each . ( )ne egg sac 1 56 . 



Innei margins of middle segments of inner rami of the natatorj legsnol with 2 

 setae each A 58. 



