Crustacean Fauna of South Africa. 203 



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. 



i. Eyes small, feebly pigmented . G. capensis n. sp. 



ii. 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 $ , 2nd antenna in very 



stout . . . . G. crassicornis n. sp. 



ii. Brown, 1st peraeopod modified in 

 adult (J, 2nd antenna in adult 

 J with an ear-like lobe on 3rd 

 peduncular joint . . G. auricularius, n. sp. 



GAMMARUS CAPENSIS n. sp. 

 (Plate XXVII. Figs. 20-22.) 



Head nearly as long as first 2 peraeou 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. 



Pleou 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 telsou, postero- inferior 

 angles of 1-3 quadrate, inferior margin of 2 with 3 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 subquadraugular, 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 3rd pleon segment, its peduncle to 

 end of penultimate peduncular joint of 2nd antenna, 1st and 2nd 



