NO. 1050. AMERICAN SPECIES OF SYNALPHEU8—C0VTIERE. 87 



The propoi-tions of the .small chela are: rin<>ers 1; total lena;th 3; 

 hei<!:lit 1.17. The carpus measures only 0.4 of tiie entire chela. In 

 the females these proportions become 1, 2.66, 1.06; the fingers being 

 relatively longer, and the carj)us measures 0.45 of the entire chela. 

 The movable finger, seen from above, is oval in form and terminates 

 in three unequal teeth, situated in the same horizontal plane; it is 

 a little excavate below, and the lateral teeth mark the extremity 

 of the thin and sharp lateral margins. The tuft of hairs is still 

 present, but it is disposed in only five transverse rows, each num- 

 bering six hairs at most. This disposition is very interesting, as 

 marking one of the extremities of the series of forms which compose 

 the L^EViMANUS group. In the allied species, like S. laticeps Coutiere 

 and S. nepfiiiius Dana, the armature of hairs of the small chela 

 either does not exist or else is very nnich reduced and differently 

 disposed. 



S. rafhhi(iin\ described elsewhere, is like a second entrance into 

 the L.TiviMANiTs group through it close relations with /S'. pesca- 

 dorensis and /S. hiunguiculatus. This last species may serve to desig- 

 nate another group of forms, almost all from the Indian Ocean 

 and the Pacific, whence the L.^evimanus group seems to have sprung. 



In the second pair the first segment of the carpus and the distal 

 chela are perceptibly equal, the four other segments of the carpus 

 slightly longer. 



The proportions of the third pair are : Meropodite 2.2 ; carpus 1 ; 

 proi^odite 1.5. The meropodite is a little more than 3 times as long 

 as wide (3.1). The ischiopodite is shorter than in the other species 

 of the group, and the dactyl is also of different form, inclining to- 

 ward such forms as S. minus; the two margins converge slightly 

 and the article is as if split into two parallel hooks, the dorsal a little 

 longer. 



The height of the telson equals 1.23 times its base, 2.9 times the 

 posterior margin; the inner spines of the latter are twice as long 

 as the outer, and between them are five plumose hairs and two pairs 

 of simple hairs. 



The outer uropod bears 3 to 4 contiguous teeth and a movable spine 

 between the first two. 



The eggs give rise to zoese. 



The species is very close to S. neptunus Dana, of which I have 

 been able to examine two typical male examples from the Sooloo Sea. 

 The rostrum is slightly longer and narrower than the lateral spines 

 and 4.5 times longer than its middle width. The stylocerite is 

 shorter than the basal antennular article. The superior angle of the 

 basicerite is slightly acute, its lateral spine reaching the proximal 

 third of the median antennular article. The scaphocerite bears, in 

 both cases, a very narrow scale of the same length as the outer spine 



