394 Annals of the South African Museum. 



in some specimens these are quite distinct and pointed, in others blunt 

 and very indistinct. 



The <J of this species closely resembles in general appearance that 

 of A. corniger, but may be easily distinguished by the absence of any 

 ventral process on the 3rd peraeon segment and by the hook-like shape 

 of the posterior tubercle on the 4th segment. 



ARCTURELLA PUSTULATA n. sp. 

 (Plate XVI. Fig. 24.) 



Female. Body glabrous, moderately depressed. Head wider (across 

 the eyes) than long, autero-lateral angles subacute, with a minute point 

 in the middle of outer margin, front margin strongly concave, dorsal 

 surface quite smooth. Eyes large, oval. Peraeon segment 1 without 

 visible suture separating it from the head; segments 2 and 3 gradually 

 widening ; segments 1-3 quite smooth ; segment 4 wider (across the 

 anterior margin) than long, lateral margins not greatly expanded, 

 nearly straight, converging posteriorly, smooth except for the tubercles 

 in the posterior half, which are arranged thus : 2 in each of the postero- 

 lateral angles, a small one immediately in front of a larger one, a little 

 in front of these 2 large submedian tubercles, the extreme postero- 

 lateral angles also bluntly tubercular ; side-plate on segment 4 

 quadrangular. 



The relative development of the tubercles, however, is subject to 

 some variation as in corm^er. The 10 mm. long ovigerous $ No. A4145 

 has only very faint traces of the 2 submedian tubercles, and the 

 smaller postero-lateral ones are entirely absent, whereas the pair of 

 large ones is strongly developed, being at least | mm. in height. 



Young specimens up to 7 mm. are quite smooth dorsally. A specimen 

 8 mm. long shows the 2 submediau tubercles and the 2 large postero- 

 lateral ones ; another also 8 mm. long shows only the 4 postero-lateral 

 tubercles. 



The tubercles are low and rounded ; even when strongly developed 

 they are apically blunt 



Segment 5 longer than either 6 or 7 ; side-plates on these 3 segments 

 pendulous, not completely visible in dorsal view. 



Pleon with the first 3 segments very slightly wider than the telsou, 

 the 3rd not laterally prominent, all the sutures very indistinct, telsou 

 without any lateral teeth or projections, apex subacute, shallowly 

 notched. 



Antenna 2, 2nd joint with strong tooth on outer margin, 5th with 

 .a row of very minute denticles along lower inner margin, flagellum of 



