346 PROCEEDINGS OF THE NATIONAL MVSEVM. vol. xxxiii. 



d. Rami of second and third legs three-jointed, of first and fourth pairs two- 

 jointed; no setae on the fourth pair, those on the other pairs rudimen- 

 tary _ e. 



d. Rami of first three pairs of legs two-jointed, with plumose seta-: of 



fourth pair one-jointed, setae nonplumose /. 



d. Rami of second and third legs two-jointed; of fourth pair one-jointed; 

 exopods of first pair one-jointed, endopods two-jointed. 



Gangliopus Gerstaecker, 1854, p. 350. 

 d. Rami of first and second legs two-jointed; of third and fourth pairs one- 

 jointed and very rudimentary; three pairs of dorsal plates. 



Perissopus Steenstrup and I.iitken, 1861, p. 352. 

 (/. Rami of third legs two-jointed, of all the other legs one-jointed, lamellar 



and without spines or setse Laminifcra Poche, 1902, p. 361. 



e. Dorsal plates on fourth segment large, covering half the genital segment or 

 more; sixth segment not separated; exopods of second and third legs three- 

 jointed, all the other rami two-jointed. 



Echthrogaleiis Steenstrup and Liitken, 1861, p. 362. 



e. Sixth segment distinctly separated as a median lobe or lamina, attached to 



the posterior sinus of the genital segment, and armed with a pair of dorsal 



plates and a rudimentary pair of swimming legs; both rami of the second and 



third legs three-jointed Dinematura Latreille, 1829, p. 374. 



/. Sixth segment distinctly separated as a rudimentary plate or lamina, 

 attached to the posterior sinus of the genital segment; anal laminae 

 transformed into horny conical processes; four pairs of dorsal plates, the 



fourth on the genital segment Pandarus Leach, 1816, p. 387. 



/. No sixth segment; anal laminse normal; second and third thorax segments 

 fused inter se, and carrying a pair of good-sized lateral lol^es; a single pair 

 of dorsal plates, on the fourth segment, close together, and with their bases 



fused Nesippus Heller, 1865, p. 424. 



/. No sixth segment; anal laminiie normal; second and third segments dis- 

 tinct, with small lateral lobes; a single pair of dorsal plates, on the fourth 

 segment, feebly developed, and widely separated, their margins fringed 



with hairs Prosifies, new genus name, p. 439. 



g. Rami of all the swimming legs two-jointed h. 



g. Rami of fourth legs one-jointed, of all the others two-jointed i. 



g. One or Itoth rami of the second and third legs three-jointed, of all the others 



two-jointed Ic. 



h. An accessory lobe on the posterior margin of the carapace just inside each 

 posterior lobe; both the fifth and sixth legs visi])le on the genital segment; 



abdomen two-jointed, the joints equal Pandanis Leach, 1816, p. 387. 



h. Second maxillipeds not swollen, with ordinary terminal claws; anal laminse 

 very large; no legs visible dorsally on the genital segment. 



Demoleus Heller, 1865, p. 349. 

 h. Second maxillipeds much swollen, with a long terminal claw; anal laminse 

 medium size; no legs on the genital segment, or but one pair. 



Perissopus Steenstrup and Liitken, 1861, p. 352. 

 i. Free thorax segments two or three times as wide as long; fourth segment the 

 longest; no legs visible on the genital segment; abdomen one-jointed. 



Nesippus Heller, 1865, p. 424. 

 i. Free thorax segments orbicular, all about the same width, second segment the 

 longest, with large lateral wings; genital segment with one pair of legs at the 

 posterior corners; abdomen two-jointed, basal joint the larger. 



Gangliopus Gerstaecker, 1854, p. 350. 



