2 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. 59. 



the genital segment, the presence of legs at its posterior corners, and 

 the one-jointed abdomen. 



Specific characters of male. — Carapace similar to that of mature 

 female, about the same length and width, nearly twice the length or 

 the rest of the body; free thorax (fourth) segment the same width 

 as the genital segment ond one-third as long; genital segment 

 obovate, three-fourths as wide as long, with a pair of fifth legs on 

 its lateral margins, a little behind the center, and a pair of sixth legs 

 at the posterior corners. 



Abdomen a little more than half the width of the genital segment, 

 two- jointed, the terminal joint twice the length of the basal; anal 

 laminae large, curved inward at the tips, and armed with long 

 plumose setae. 



Appendages in general like those of the female, but the second 

 antennae are stouter, as is usual in the male, and are armed with 

 several accessory knobs and adhesion pads. The first maxillae are 

 rather short, stout, and almost perfectly straight; the outer branch 

 at the tip is twice the length of the inner, and the latter has a wide 

 flange along its inner margin. 



Color (preserved material) dark yellowish gray. 



Total length, 3.75 mm. Length of carapace, 2.35 mm.; width, 

 2.25 mm. Genital segment, 0.65 mm. long, 0.50 mm. wide. 



Remarks. — When the species was originally established in 1905 * 

 no males had been discovered, and there were no data as to localitjr 

 and host. Afterwards 20 females were obtained from the jewfish 

 (Stereolepis gig as) by Dr. J. C. McClendon at La Jolla, California. 

 These were recorded 2 and bear Cat. No. 38567, U.S.N.M. The 

 present specimens are from the same general locality, but from 

 another host. They furnish additional evidence that the species 

 belongs to the Pacific coast, and they supplement the original 

 description by adding the male sex and a development stage. 



ALEBION FUSCUS, new species. 



Plate 1, figs. 6-11 ; plate 2, fig. 12. 



Host and record of specimens. — Five females were obtained from 

 the outer surface of a dusky shark, Carcharhinus obscurus, at Woods 

 Hole in 1891 by Vinal Edwards. The specimens are somewhat 

 curled and shriveled, as though they had suffered at some time from 

 the drying up of the alcohol; but the best has been selected as the 

 species type with Cat. No. 43559, U.S.N.M. 



The other four become paratypes with Cat'. No. 43560, U.S.N.M. 



Specific characters of female. — Carapace ellipsoidal, one-fifth 

 longer than wide and evenly rounded. Posterior sinuses narrow and 



1 Proc. U. S. Nat. Mus., vol. 28, p. 618. 2 Idem, vol. 35, p. 440. 



