14 Annals of the South African Museum. 



A male and a young female specimen, captured by Mr. Max 

 Schlechter in Little Bushmaiiland along the road leading from 

 Steinkopf to Eamond's Drift on the Orange River, Namaqualand. 

 They live in burrows in sandy ground. Mr. Schlechter found 

 0. walilbcrgi living in the same locality. 



In the male specimen described above the carapace is as long as 

 the first and second caudal segment and one-half of the third, hence 

 possibly not quite full grown. It is so well characterised, however, 

 especially by the smoothness and the absence of crests on the under 

 surface of the first four caudal segments, that I have not hesitated to 

 describe it. 



OPISTHOPHTHALMUS GEANICAUDA, n. sp. 

 Male (recently killed, in alcohol}. 



Colour of carapace and cauda brownish yellow to olive-brown ; 

 legs and vesicle pale-ochraceous ; arms ochraceous to ochre-brown ; 

 abdomen brown or olivaceous with the hind edge of the segments 

 brown ; the crests of the palps, the fingers, the mandibles, and the 

 crests above the median and lateral eyes black or dark olive-green. 



Carapace longer than wide, as long as the first and second caudal 

 segment ; its interocular area coarsely or weakly granular in front, 

 nearly smooth on the convexities behind ; sides of the carapace 

 granular, coarsely so along the borders of the interocular area ; 

 median eyes more than a quarter of the length of carapace from 

 posterior edge ; median groove distinctly forked in front. 



Terga densely and finely granular throughout, the last segment 

 with coarser granulation at the sides, the third to sixth segment 

 with a weak, granular, median keel, the seventh with a low, finely 

 granular, median elevation and two low, coarsely granular, posterior- 

 elevations. 



Sterna. Segments 1-4 finely granular at the lateral borders, their 

 surface finely rugose or the anterior ones smooth ; fifth segment keel- 

 less, very densely and finely granular or rugoso-granular throughout, 

 as is also the ventral surface of the first four caudal segments. 



Cauda moderate ; the granulation of the upper surface for the 

 most part confined to the sides, strong in the anterior, sparse in the 

 posterior segments, the fifth segment smooth above ; upper crests 

 granular, the terminal tooth usually (but not always) enlarged and 

 spiniform on segments 2-4 ; upper lateral crests well developed, 

 granular, on segment 5 weak, and present only in the anterior half ; 

 infero-lateral keels practically obsolete in segments 1-4, least so in 

 segment 4, where a row of slightly enlarged granules often indicates 



