206 Annals of the South African Museum. 
GAMMARUS NIGROCULUS NU. sp. 
(Plate XXVII. Fig. 23.) 
Head not equal to first 2 peraeon segments, antero-lateral lobe 
rounded. Eyes moderate, oval, set close to the margin of the lobe. 
Side-plates 1-4 as deep as their segments, inferior margin of 1-3 
rounded, setose but less so than in capensis, of 4 sparsely setose, 
antero-inferior angle rounded, postero-lateral angle subacute. 
Pleon segments 1—3 with a few short setae, 4-5 with more numerous 
and longer setae on posterior margin, 6 with a submedian group of 
4 setae and 1 spine on either side near base of telson, postero-inferior 
angle of 3 quadrate, without produced point, posterior margin with a 
few shght setiferous indents, inferior margin of 1-3 sparsely setose, 
the setae not arranged in transverse rows. 
Telson as long as broad, cleft nearly to base, lobes dehiscent only at 
apex, tapering slightly, apices rounded, margins and apices setose, 
1 large spine on upper surface just beyond middle of outer margin. 
First antenna reaching to end of peraeon, the peduncle to middle 
of ultimate peduncular joint of 2nd antenna, 2nd joint 2 Ist, 3rd 
3 2nd, flagellum at least twice as long as peduncle, accessory flagellum 
4-jointed. 
Second antenna a little stouter than and about half the length of 
Ist, gland-cone acute, reaching nearly to end of 3rd joint, 4th and 5th 
subequal, flagellum equal to peduncle, ca. 17-jointed. 
Mandibles, cutting-edge 5-dentate in left, in right 4-dentate, 
secondary cutting-edge 3 dentate in left, in right a 4-pronged tubercle, 
spine-row with ca. 5 spines, 2nd joint of palp scarcely 22 times as long 
as broad, 3rd equal to 2nd, elongate-diamond shaped, thrice as long 
as broad. 
First and second gnathopods similar but Ist a little shorter and 
stouter, 6th joint not half as long again as 5th, equal in width to 5th, 
oblong, not distally widened, palm slightly oblique, gently convex, 
defined by 2 spines, finger matching palm. 
First and second peraeopods nearly as spinose as in capensis, but 
much less setose, especially 2nd and 4th joints, hind margin of 5th 
with 5 spines, of 6th with 6 groups of 1 spine and*2 setae each, 7th 
with 3 spine-setae on inner margin. 
Third to fifth peraeopods, 2nd joint oval, anterior margin spinose 
but not setose, hind margin serrulate and setose, convex in 3rd peraeo- 
pod, straight in distal half in 4th and 5th peraeopods, postero-inferior 
angle rounded, reaching to middle of 3rd in 8rd peraeopod, to end of 
