104 U.S. NATIONAL MUSEUM BULLETIN 2 59 



Diagnosis. — A large subterranean species distinguished by the 

 rather setose and spinose 4th and 5th peduncular segments of antenna 

 2, broad 2nd palpal segment of maxilliped, broad posterior margins of 

 pereopod bases, and by having up to 25 relatively short apical spines 

 on telson. Further distinguished from S. osarkensis, to which it is 

 somewhat closely allied, by broader bases of pereopods, fewer apical 

 spines on 3rd uropod, absence of lateral spines on telson, proportion- 

 ately shorter telson in the male, and larger size at maturity. Largest 

 males, 19.50 mm; largest females, 18.00 mm. Sexes generally similar. 



Antenna 1 usually 50 to 65 percent as long as body, about 40 percent 

 longer than antenna 2; primary flagellum with up to 40 or more 

 segments; accessory flagellum short, extending about the length of 

 1st primary flagellar segment. Antenna 1 of female proportionately 

 a little less long, primary flagellum with a few less segments. An- 

 tenna 2: peduncular segments 4 and 5 with a number of coarse, 

 bristle-like setae on ventral margin, segment 4 with a few additional, 

 slender spines on ventral margin; flagellum with up to 15 segments in 

 both sexes. Mandible: molar process rather poorly developed; palpal 

 segment 3 with about 10 long setae, segment 2 with 10 to 12 setae. 

 Maxilla 1, inner plate with 6 comparatively short, apical, plumose 

 setae. Maxilla 2, inner plate with 7 long, obliquely placed, plumose 

 setae. Maxilliped: outer plate not reaching to apex of 1st palpal 

 segment; palpal segment 2 broadly expanded, only about 35 percent 

 longer than broad. Lower lip, inner lobes moderately well developed 

 but rather narrowly rounded apically. 



Gnathopod 1 : propod palmar margin oblique, nearly straight, armed 

 with a double row of 10 or 11 spine teeth; posterior angle with 1 large 

 spine and 5 smaller spines on outside, 6 small spines on inside; pos- 

 terior margin with 3 sets of setae; superior lateral setae few or lacking, 

 inferior lateral setae mostly doubly inserted; claw of dactyl rather 

 short. Gnathopod 2: propod palmar margin less oblique, straight, 

 armed with a double row of 10 or 11 spine teeth; posterior angle with 

 1 large spine and 6 smaller spines on outside, 7 or 8 small spines on 

 inside; posterior margin with 7 sets of setae; superior lateral setae in 

 sets of 3's and 4's, inferior lateral setae in sets of 2's and 3's; dactyl 

 claw short; coxal plate broad, with about 8 setae and 2 spinules 

 marginally. Coxal plate of pereopod 3 broad, marginally with about 

 8 setae and 3 spinules; that of pereopod 4 between 20 to 25 percent 

 broader than long, marginally with 9 or 10 setae. Pereopod 7 approx- 

 imately 50 percent as long as body, a little longer than pereopod 6 

 and 40 percent longer than pereopod 5. Bases of pereopods 5-7 about 

 as broad proximally as distally; posterior margins gently rounded; 

 distoposterior lobes broad. Dactyls of pereopods 6 and 7 rather short, 

 only about 20 to 25 percent as long as corresponding propods; that of 



