AN AMPHIPOD FROM THE TRANSVAAL. 951 



gonyx uropod 3 not elongate, so also N'eoniphargtis whicli has 

 inner ramus minute ; Nifhargus has outer ramus long, two- 

 jointed, and the inner small. 



Telson with emargination and almost square, as in E . vejdovshyi ; 

 in Crangonyx entire or partly cleft ; in Paracrangonyx entire ; 

 in Neoniphargus jmrtly cleft ; in Niphargus deeply cleft. 



This evidence seems sufficient to warrant the inclusion of 

 this new species in the genus Eucrangonyx near the species 

 E. vejdovskyi. 



I have taken the opportunity here offered of naming the species 

 after the Rev. Noel Roberts, in recognition of his enthusiasm for 

 this branch of zoology. 



Detailed descrip)tion of the neiu S2)ecies. 



Family GAMMARIDJE Leach. 

 Genus Eucrangonyx Stebbing. 

 Eucrangonyx robertsi, sp. n. (Plate XLIX.) 



Female: length of largest specimen taken 11 mm.*; colour 

 dirty yellow or pink in the shallower cave near Potgietersrust, 

 semi-transparent white in the deeper cave. No trace of eyes 

 was discovered. 



Body rather compressed, smooth, no carina, rostrum barely 

 perceptible, a few minute spines on dorsal part of head and third 

 segments ; the last three or five segments with spines on posterior 

 margin. 



First four coxal plates of pereion deeper than the rest, the first 

 smallest, the third and fourth deepest ; the fourth plate broader 

 than the others-; side-plates of the iifth, sixth, and seventh 

 pereion segments small, those of fifth and sixth deeply emarginate 

 behind. These coxal plates bear marginally small spines. 



Antenmdes (PI. L. fig. 1) long, longer than the antennse ; 

 flagellum much longer than the peduncle ; first joint of the 

 peduncle a little shoi'ter than second and third joints together ; 

 second joint rather longer than third ; accessory flagellum (PI. L, 

 fig. 1 a) two-jointed — both joints armed with setse, — minute, 

 hardly as long as first joint of flagellum ; all the joints of the 

 antennule provided at their distal extremity with moderate setee, 

 of which one or two on each segment are conspicuously longer 

 than the rest ; the second joint of the peduncle has also two 

 groups of small setse and one other seta besides about its middle 

 length ; the arrangement of the setee on each joint of the flagellum 

 appears to be constant in disposition after the eighth joint, and 

 to be about seven in number. 



A^itennce (PI. L. fig. 2) about four-sevenths the length of the 



* The length includes that part from the anterior margin of the head to the 

 posterior margin of the last pleon segment. 



65* 



