COPEPODS OF THE WOODS HOLE REGION 619 



49. Caudal rami uncinate; second maxillae much longer than 



maxillipeds; first antennae 3-segmented, setose; second 

 antennae biramose, exopod 2-segmented; gills of fresh-water 



fishes cf Achtheres Nordmann, 1832 



Caudal rami large, laminate, bluntly rounded; second maxillae 

 about as long as maxillipeds; first and second antennae not 

 yet known; gills of salt-water fishes cf Epibrachiella Wilson, 1915 



50. Trunk 3-segmented; second antennae uniramose, 2-segmented; 



maxillipeds larger than second maxillae, their terminal claws 

 bent almost in a circle; mouths of fishes — cf Thysanotella Wilson, 1915 

 Trunk 4- or 5-segmented; second antennae biramose; maxillipeds 

 shorter than second maxillae, their terminal claws slender, 

 almost straight; spiracles of fishes- cf Charopinus Kr0yer, 1863 (p. 511) 



51. Caudal rami often lacking; trunk not longer than head 52 



Caudal rami always present ; trunk longer than head 53 



52. No dorsal carapace; first antennae 1-segmented; second anten- 



nae uniramose, 1-segmented; second maxillae considerably 



longer than maxillipeds; gills of fishes cT Vanbenedenia Malm, 1860 



A distinct carapace; first antennae 3-segmented; second 

 antennae biramose; second maxillae and maxillipeds usually 

 same length; gills of fishes cf Brachiella Cuvier, 1830 (p. 520) 



53. No dorsal carapace; first antennae 3-segmented; second anten- 



nae biramose; maxillae and maxillipeds with falcate claws, 

 sometimes twisted badly; giUs of fishes. cT Thysanote Kr0yer, 1863 (p. 509) 

 A distinct carapace; first antennae 4-segmented; second an- 

 tennae uniramose, 4-segmented, with apical chela; maxilli- 

 peds longer than second maxillae; skin of sharks. 



cf Lernaeopoda Blainville, 1822 



54. Head and anterior trunk fused and covered with a carapace; 



second antennae biramose; second maxillae longer than 



maxilHpeds; gills of fishes cf Naobranchia Hesse, 1863 



Head and trunk separated, no dorsal carapace; second antennae 

 uniramose; second maxillae and maxillipeds same length, 

 chelate; gills of fishes cf Probrachiella Wilson, 1915 



55. Body bent once, head at right angles to trunk 56 



Bodj' bent twice, anterior head and posterior trunk parallel and 



at right angles to middle of body 57 



Body folded and completely fused, with no distinction of parts 58 



56. No dorsal carapace; second antennae biramose, rami 1-seg- 



mented; first maxillae tripartite; caudal rami small, without 



setae; gills of fishes cf Parabrachiella Wilson, 1915 (p. 519) 



A distinct carapace; second antennae uniramose, 3-segmented, 

 with stout apical claw; first maxillae bipartite; no caudal 

 rami; gills of fishes cf Eubrachiella Wilson, 1915 



57. Head separated from trunk; each ramus of second antenna and 



first maxilla with 2 apical spines; caudal rami present; gills 



of rays cf Lernaeopodina Wilson, 1915 



Head fused with trunk; rami of second antenna without spines; 

 first maxilla with 3 apical spines; caudal rami not present; 

 fins of fishes cf Clavellopsis Wilson, 1915 



