86 U.S. NATIONAL MUSEUM BULLETIN 2 59 



palmar margin of gnathopod 1, slightly convex propod palmar mar- 

 gin of gnathopod 2, larger number of spine teeth on palms of both 

 gnathopodal propods, proportionately shorter outer ramus of uropod 

 2, less elongate telson of male, and more apically spinose telson of 

 female. Largest male, 6.00 mm; largest females, 9.00 mm. 



Female. — Antenna 1 up to 65 percent as long as body and 50 per- 

 cent longer than antenna 2; primary flagellum with up to 29 segments; 

 accessory flagellum a little longer than primary flagellar segment 1. 

 Antenna 2: ventral margin of 4th peduncular segment with a few 

 slender spines; flagellum with 11 segments. Mouth parts corre- 

 sponding closely to those of S. alabamensis except that inner plate of 

 maxilliped has only 3 thick, apical spines. 



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

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

 and 3 smaller spines on outside, 5 small spines on inside; posterior 

 margin with 3 sets of setae; superior lateral setae represented by a 

 single triply inserted set, inferior lateral setae singly inserted; dactyl 

 claw rather long. Gnathopod 2 : propod palmar margin slightly con- 

 vex, armed with a double row of about 12 spine teeth; posterior angle 

 with 1 large spine and 2 smaller spines on outside, 4 small spines on 

 inside; posterior margin with 4 sets of setae; superior lateral setae 

 doubly and triply inserted, inferior lateral setae singly inserted; 

 dactyl claw rather long. Coxal plates of pereopods 2, 3, and 4 similar 

 proportionately to those of three previously described species, ^\dth 

 6, 8, and 7 (or 8) marginal setae, respectively. Pereopod 7 about 

 50 percent as long as body, a little longer than 6, up to 40 percent longer 

 than 5. Dactyls of pereopds 5-7 about 1/3 as long as corresponding 

 propods. Bases of pereopds 5-7 similar to those of S. alabamensis 

 and S. montanus and as shown in figure 20. All gill structures present. 



Abdominal side plates: posterior margins convex, with 3 to 5 setae 

 each; posterior corners rounded; ventral margins of j^late 2 with 1 

 spine, that of plate 3 with 4 spines. Pleopod 1, inner ramus 40 to 45 

 percent longer than peduncle. Uropod 1 : inner and outer rami about 

 equal in length, approximately 60 percent as long as j^eduncle; outer 

 ramus armed with 10 or 11 spines; inner ramus with 9 or 10 spines; 

 peduncle with 15 spines. Uropod 2: outer ramus about 60 percent as 

 long as inner ramus, about 45 percent as long as peduncle, armed with 

 5 or 6 spines; inner ramus with 10 spines; peduncle with 5 spines. 

 Uropod 3, ramus about 30 percent as long as peduncle, armed apically 

 with 3 unequal spines. Telson about 40 percent longer than broad, 

 convex apical margin with 17 or 18 unequal spines. 



Male (allotype). — Generally similar to female but smaller in the 

 single specimen at hand and differing in a few minor details as follows: 

 Antenna 1 up to 65 percent as long as body and 50 percent longer than 



