64 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. xxxvi. 



The third pair is very robust in the male. The relative dimensions 

 are : Meropodite 2.33 ; carpus 1 ; propodite 1.6 ; the meropodite is only 

 3 times as long as wide; the dactyl has its two hooks almost equal, 

 the ventral a little stronger. 



In the female the proportions remain the same, but the dimensions 

 of the second and third pairs are noticeably less (about 0.8). 



The height of the telson is 1.2 times the width at the base, and 

 3.9 to 4 times the posterior margin, the last dimension as in the males; 

 the border bears 4 equal and almost equidistant spines, including be- 

 tween them, on a narrow, convex portion of the margin, 5 hairs, of 

 which 3 are large and plumose; the spines of the upper surface are 

 longer than those of the margin. 



The outer border of the uropod bears C to 8 spines, the first large, 

 continuing the border of the suture, the second and following rapidly 

 diminishing; only the last or the last t^yo are not mobile. 



The eggs give rise to zoese. 



I have never met with any vestige of an antennal scale ; on the other 

 hand, a male {Fish Hawk Station No. 7124) shoAvs an interesting 

 variation in the length of the antennal spines, which do not reach to 

 the extremity of the median antennular article; this specimen indi- 

 cates the way in which iS. pandionh^ the next American species de- 

 scribed, has become differentiated. 



One female {Grampus Station No. 5116), of which all the eggs are 

 hatched, and the zoea? are still present under the abdomen, shows the 

 opposite variation ; both the antennal spines equal the antennule, and 

 are also thicker than usual ; the stylocerite is also a little longer. 



Localities : 



Gulf of Mexico: 



Lat. 26° 30' N., long. 83° 30' W., 33 fathoms, Grampus Sta- 

 tion No. 5116, a female (not quite typical). 

 Lat. 26° 33' N., long. 83° 10' AY., 28 fathoms, Fish Hawk 



Station No. 7123, 1 male. 2 females, types. 

 Lat. 25° 50' 15" N., long. 82° 41' 45" W., 21 fathoms, Fish 



TIawh Station No. 7124, 2 males, 3 females. 

 Lat. 27° 04' 00" N., long. 83° 21' 15" W., 26 fathoms, 

 Alhatross Station No. 2409. 

 njpe.—C'dt. No. 38399, U.S.N.M. 



The species is very close to the one that I described in a previous 

 paper under the name S. hiri7nanus var. parfaifi, and which should 

 also be separated as a distinct species. It is unfortunately repre- 

 sented by a single female, of which the small chela is missing. 



The frontal teeth and the rostrum are separated by wider intervals 

 with divergent margins; the lateral teeth are wider at the base and 

 less obtuse at the extremity ; the rostrum is on a level with them, and 



