COPEPODS OF THE WOODS HOLE REGION 419 



the abdomen, in the male usually smoothly rounded. Abdomen 

 2-segmented in both sexes, the basal segment in female with long 

 processes at its posterior corners ; caudal rami large with long setae. 

 First three pairs of legs biramose, the exopods with very large horny 

 claws; rami of first pair 2-segmented, of second and third pairs 

 3-segmented; fourth legs rudimentary, consisting of a single seg- 

 ment; no furca or maxillary hook; leg rudiments often present in 

 the male on genital segment. 



KEY TO THE SPECIES 



FEMALES 



1. Genital segment quadrangular, with rounded corners and with- 



out posterior processes glaber (p. 419) 



Genital segment elliptical, with long conical processes, extend- 

 ing beyond tip of abdomen 2 



2. Carapace distinctly longer than wide, median lobe broad, reach- 



ing far behind tips of lateral lobes 3 



Carapace as wide as long or wider, median lobe not reaching 



tips of lateral lobes or but little beyond them 4 



3. Dorsal plates on fourth segment widely separated, not fused at 



base, each lunate with indented inner margin gracilis (p. 420) 



Dorsal plates on fourth segment fused at base, each semiellip- 



tical, with straight inner margin fuscus (p. 421) 



4. Posterior processes of genital segment conical, smooth, inclined 



outward, and quite slender carchariae (p. 422) 



Posterior processes of genital segment flattened laterally, thick, 



fringed with spines, inclined inward crassus, new species (p. 423) 



MALES 



1. Genital segment with small triangular processes at its posterior 



corners; fifth legs visible dorsally glaber (p. 419) 



Genital segment with smoothly rounded posterior corners, no 

 processes ; no fifth legs visible dorsally 2 



2. Genital segment elliptical, widest at center, one-third longer 



than wide, with convex lateral margins gracilis (p. 420) 



Genital segment oblong, widest at anterior end, twice as long as 



wide; with straight lateral margins crassus, new species (p. 423) 



ALEBION GLABER Wilson 

 FlQUBE 263 



Alebion glaber Wilson, Proc. U. S. Nat. Mus., vol. 31, p. 708, pi. 19, 1907. 



Ocam^ence. — Found on the outside surface of the smooth dogfish, 

 the spiny dogfish, the sand shark, the barn-door skate, the brown 

 shark, and the bonito, all captured near Woods Hole. 



DistHhution. — Not found outside the present area. 



Color. — Body a uniform horn gray, semitransparent, and without 

 pigment marks. 



