608 BULLETIN 159, UNITED STATES NATIONAL MUSEUM 



33. Males only; abdomen visible in dorsal view; second and third 



segments forming waist between head and fourth segment; 

 fourth rami lamellar; outside of fishes. 



cf Orthagoriscicola Poche, 1902 (p. 443) 

 Both sexes; abdomen entirely concealed in dorsal view; second 

 and third segments as wide as fourth, no waist; fourth rami 

 narrow conical; outside of fishes. 



cf 9 Philorthragoriscus Horst, 1897 (p. 444) 



34. Abdomen as large as genital segment, both with broad lateral 



wings between which the long egg strings are coiled and 



concealed; gills of fishes ? Cecrops Leach, 1816 (p. 441) 



Abdomen smaller than genital segment, both without wings; 

 egg strings long but entirely visible, and neither coiled nor 

 convoluted; outside of sharks 9 Achtheinus Wilson, 1908 



35. Four pairs of dorsal plates, the halves of first 3 pairs entirely 



separated, of fourth pair fused, with a posterior sinus; fins 



of sharks 9 Perissopus Steenstrup and Liitken, 1861 (p. 424) 



Two pairs of dorsal plates, partly fused with serrate margins; 

 first pair with posterior sinus, second pair overlapping on 

 midline; outside of fishes 9 Orthagoriscicola Poche, 1902 (p. 443) 



36. Rami of first, second, and fourth legs 1-segmented; of third 



legs 2-segmented; 3 pairs of dorsal plates, each wider than 



the carapace; outside of sharks 9 Phyllothyreus Norman, 1903 



Rami of first legs 2-segmented, of second and third legs 3-seg- 



mented 37 



37. Fourth segment without dorsal plates; rami of fourth legs 



3-segmented; leg rudiments on genital segment; urosome 



shorter than metasome; gills of fishes cf 9 Dissonus Wilson, 1906 



Fourth segment with dorsal plates; rami of fourth legs laminate, 

 1-segmented; no leg rudiments on genital segment; urosome 

 longer than metasome; outside of sharks. 



9 Dinematura Burmeister, 1833 (p. 430) 



38. Exopod of first legs 1-segmented, endopod 2-segmented; rami 



of second and third legs 2-segmented, of fourth legs 1-seg- 

 mented; 3 pairs of dorsal plates; gill cavity of sharks. 



9 Gangliopus Gerstaecker, 1854 

 Rami of first legs 2-segmented, second and third exopods 3- 

 segmented, endopods 2-segmented; fourth rami 1-segmented 

 in female, in male exopod 3-segmented, endopod 2-segmented; 

 outside of sharks. 



cf 9 Echthrogaleus Steenstrup and Liitken, 1861 (p. 426) 



39. Rami of first 4 pairs of legs 2-segmented 40 



Rami of first 3 pairs of legs 2-segmented, fourth pair 1-seg- 

 mented 43 



One or both rami of second and third legs 3-segmented, the 



others 2-segmented 46 



40. Abdomen 1-segmented; caudal rami small and semicircular; 



maxillipeds moderately swollen, with chelate claw shutting 

 on 2 knobs; fins of sharks. 



cf Perissopus Steenstrup and Liitken, 1861 (p. 424) 

 Abdomen 2-segmented; caudal rami large and foliaceus 41 



