ies of Opisthophthahniis. 175 



granular in the male ; the posterior tarsi, also, have 2 external 

 spines below. 



Syno2)sis of the Species of OPISTHOPHTHALMUS 

 in the collection of the South African Museum. 



A. Median groove of carapace with a well-developed Y-shaped fork in front. 

 enclosing the anterior median depression. 



A 1 . Median eyes far forward, their distance from anterior margin not exceed- 

 ing 1J times their distance from posterior margin. Bushnianland (Cape 

 Colony), German South- West Africa, Rhodesia . . <? ? O. carinatus (Pet.). 



B 1 . Median eyes farther back. (A synopsis of the species referred to here 

 has already been given on p. 30 of this volume.) 



B. Median groove of carapace not distinctly forked (occasionally with a partially 

 developed fork) in front. 



a. Median eyes situated almost in the middle of the carapace. Bushrnan- 

 land (Cape Colony), German South- West Africa. . <? ? 0. wahlbergi (Thor.). 



b. Median eyes situated far behind the middle of the carapace. 



a 1 . Superior terminal lobe of tarsus at least as long as the lateral lobes, 

 cylindrical and very thick, being several times as thick as the claws at 

 their base and provided with half a dozen long stout bristles. Anterior 

 surface of hurnerus very wide, almost as wide as the upper surface in 

 the middle. German South- West Africa . . ? 0. flavescens, Pure. 



b 1 . Superior lobe of tarsus slender or short. Anterior surface of humerus 

 much narrower than the upper surface in the middle. 



a-. Sides of the carapace coarsely granular, at least in the anterior 

 half. 



s. Operculuui completely cleft longitudinally and provided with a 

 pair of stylets on upper surface behind. (Males.) 



a 4 . Superior crests of cauda with enlarged terminal tooth in 

 segments 2-4. Length of hand-back considerably exceeding 

 the breadth of hand in adult. 



a 5 . Scape of pectines rectangular at the base behind and 

 toothed along the whole posterior margin. Anterior 

 caudal and posterior abdominal segments finely and 

 densely granular below. Victoria West, Beaufort West, 



Prince Albert, and Robertson Divisions 



cT 0. karroocnsis, Pure- 



b=. Scape of pectines obtuse or rounded at the base behind, 

 the hind margin free of teeth for some distance at the 

 base. 



a 6 . Ventral surface of abdominal and anterior caudal 

 segments densely and coarsely granular. Bushman - 

 land (Cape Colony) . . . . 30. longicaudu, n. sp. 



