Crustacean Fauna of South Africa. 205 
Key to the South African species described below : 
1. 4th side-plate normal, i.e. different from the preceding side- 
plates, palm of gnathopods slightly oblique. 
1. Eyes small, feebly pigmented . G. capensis n. sp. 
u. Eyes large, deeply pigmented . G. nigroculus n. sp. - 
2. 4th side-plate rectangular, similar to the preceding side-plates, 
palm of gnathopods transverse. 
i. White, 1st peraeopod not modified 
in f, 2nd antenna in ¢ very 
stout : : : . G. crassicornis ni. sp. 
ii. Brown, Ist peraeopod modified in 
adult ¢, 2nd antenna in adult 
$ with an ear-like lobe on 3rd 
peduncular jomt . : . G. auricularius, 0. sp. 
GAMMARUS CAPENSIS Nn. Sp. 
(Plate XXVII. Figs. 20-22.) 
Head nearly as long as first 2 peraeon segments together. Antero- 
lateral angles rounded. Eyes very small, circular, with whitish 
pigment, glistening, in spirit becoming invisible. Peraeon segments 
5-7 frequently with a few short setules on posterior margins. 
Side-plates 1-3 as deep as their segments, 4 a little deeper and 
broader than the preceding ones, inferior margins of 1-4 convex and 
setose, antero-inferior angle of 4 rounded, postero-lateral angle 
sharp, anterior lobe of 5 not as deep as 4. 
Pleon segments 1-3 with a fringe of fine setae on posterior dorsal 
margin, 4-6 with longer and more numerous setae, 6 in addition with 
2-3 spines on either side near the base of the telson, postero-inferior 
angles of 1-3 quadrate, inferior margin of 2 with 5 spines and a few 
marginal setae, of 3 with 4 spines and a few marginal setae (the 
spines and setae not arranged in transverse rows), posterior margin of 
3 with slight setuliferous indents. 
Telson as long as broad, cleft almost to base, lobes dehiscent only at 
apex, each lobe subquadrangular, apically obliquely truncate, with 
2 apical bundles of long setae and 1 spine on outer apical angle, 
1 bundle of setae in middle of the distal half and another on outer 
margin a little more than one-third from base. 
First antenna reaching to end of 8rd pleon segment, its peduncle to 
end of penultimate peduncular joint of 2nd antenna, Ist and 2nd 
