146 
Transactions of the Royal Society of South Africa. 
of hand quite smooth and rounded in the female, 
nearly flat and almost smooth in the adult male ; 
pectinal teeth, male 22-29, female 15-22 . . 0. loahlhergi Thor. 
All the sternites of the male but only the last in the 
female with flattened tubercles ; vesicle smooth below ; 
hand with flattened reticulating tubercles in both 
sexes ; pectinal teeth, male 21, female 33 . .0. adustus Kraep. 
b. Frotarsus of legs I and II usually toith 3 long strong spines and 
some stiff hairs on the outer side; tarsus III and tistially IV 
loith 1-2 spines on the outer side irtferiorly {^except in ecristatus). 
(a--be.) 
a-. Fourth caudal segment infcriorly ivithout trace of a median 
Iceel, quite rounded as in the preceding segments; carapace 
groove only indistinctly forked. {2? and b^.) 
a'\ Sternites and under surfaces of tail smooth and polished, 
flnely punctured. Carapace with smooth spaces behind 
and lateral to the eye tubercle . . . .0. schultzei, Kraep. 
b^. Sternites and first four caudal segments inferiorly 
strongly wrinkled transversely. Cai'apace uniformly 
granular except just in front of the eye tubercle 
Male of O. undulatus Kraep. 
b". Fourth caudal segment inferiorly tvith distinct granular or 
smooth median keels or at any rate granulated, (a'^-b^,) 
a''. Carapace groove very distinctly forked in front ; inferior median 
keels well developed in caudal segment II. (a^ and b^.) 
a'. Upper and outer surfaces of hand quite distinct ; vesicle 
almost smooth inferiorly, only granulated just at the 
base if at all : last sternite quite without keels . O. carinatus, Ptrs. 
b^. Upper and outer surfaces of hand completely merging, 
the finger keel being quite obsolete ; vesicle coarsely 
punctured over the greater part of its lower surface 
and with some scattered coarse granules at the base ; 
last sternite with 4 strong smooth keels in its posterior 
half ; tarsi III and IV with only a single row of 3 spines 
inferiorly Male of O. ecristatus Poc. 
b*. Carapace groove not forked in front or only indistinctly so. 
(afi-c«.) 
a^. Tarsi IV and III Avith 2 spines on the outer side in- 
feriorly ; vesicle inferiorly with rows of granules 
extending to the sting ; interocular area usually 
somewhat granular ; pectinal teeth, male 26-28, female 
16-21, the scape being free of teeth in its basal fourth 
O. opinatus Sim. 
b**. Tarsus IV without a spine. III with 2 spines on the 
outer side inferiorly ; vesicle inferiorly with short rows 
of granules only at the base ; interocular area quite 
smooth ; pectinal teeth, female 10-12 Female of O. intercedens Kraep. 
c^. Similar to opinatus but scape of pectines toothed 
throughout, carrying 21-23 teeth in the male : inter- 
ocular area coarsely granulated . . . O. scahrifrons sp. nov- 
