132 
Trmisacflons of the Boyal Society of South Africa. 
U. an go] en sis, and I may say I have had no difficulty in the discrimination 
of the two species, with the exception of the single specimen, from Natal, 
described years ago as B. queketti, on the specific distinctness of which I am 
in doubt. As I can also distinguish the two species in their larval condition, 
1 see no reason for doubting their validity. 
The uncertainty to which allusion has been made probably results from 
the imperfection of previous definitions, and I therefore now propose to 
give detailed descriptions of the two species, based exclusively on specimens 
from South Africa and Angola, and also diagnoses by means of which I trust 
the correct naming of specimens should offer no difficulties. I nevertheless 
agree with Mr. Hewitt in regarding the two species as the extreme forms of 
one common stock. 
Diagnoses op the two Species. 
Rana fusci^ula. — Head usually a little broader than long, never longer 
than broad ; interorbital space only a little narrower than the upper eyelid ; 
tibio-tarsal articulation not reaching beyond the tip of the snout ; heels not 
or but slightly overlapping ; tibia twice in length from snout to vent, or 
slightly more or slightly less ; toes entirely or nearly entirely webbed, never 
less than f webbed, rarely two phalanges of fourth free ; glandular dorsal 
folds, if present, one only on each side, on the anterior third of the back. 
Tadpole with 5 or 6 upper and 4 lower series of labial horny teeth. 
Rana angolensis. — Head as long as broad or a little longer than broad, 
very rarely slightly broader than long ; interorbital space much narrower 
than the upper eyelid ; tibio-tarsal articulation reaching the tip of the snout 
or beyond ; heels strongly overlapping; tibia 1} to 1^ times in length from 
snout to vent ; toes f to | webbed, two or three phalanges of fourth free ; 
back, as far as the sacral region, usually with 6 or 8 more or less prominent, 
more or less interrupted glandular folds. Tadpole with 3 or 4 upper and 
3 lower series of labial horny teeth. 
Descriptions of the two Species. 
Rana fuscigula. — Vomerine teeth in oval groups or very short transverse 
or oblique series l^ctween or just behind the level of the choanae. 
Head usually a little broader than long, never longer than broad, much 
depressed ; snout rounded, rarely ohtusely pointed, feebly or scarcely pro- 
jecting beyond the mouth, as long as the eye or a little longer (up to 
1^ times) ; canthus rostralis obtuse ; loreal region very oblique, feebly concave ; 
nostril equidistant from the eye and the tip of the snout, or a little nearer 
the former ; the distance between the nostrils not or but little greater than 
the interorbital width, which is a little less than that of the upper eyelid ; 
