434 Me. oldfield thomas o^ [May 4, 



Boror specimeiis fjtoved to be, Senna and Tette were the localities 

 first named by him. 



In a previous communication to the Society ', Mr. Thomas had 

 stated that in Petrodromus there was a considerable difference in size 

 between the sexes ; but this statement he bad now to withdraw, 

 as it proved to have been based on a confusion of species, and a 

 careful comparison now showed that there was no essential 

 difference in size or in other characters between the two sexes. In 

 confirmation of this it might be noted that as regards the allied 

 genus Macroscelkles, of ] 5 skulls of M. /kscks from Mashonaland 

 and Matabililand, there seemed no appreciable difference in size 

 between the two sexes. 



Similarly there appeared to be no cUfferences between the sexes 

 as regards the character of the hairs on the under surface of the 

 tail, peculiarities which were first described by Dr. Giinther ^ and 

 then by Dr. Matschie ^; and these bad been, especially by the latter, 

 regarded as in some way connected with sex. Now, however, it 

 appeared that both sexes possessed tail-like bristles of the same 

 nature, and that the structure of these formed very good specific 

 characters. 



The following were diagnoses of the three species recognized by 

 Mr. Thomas : — 



1. P. TETEABACTYLUS, Pet. 



Tail well-haired, the hairs perfectly simple and normal, not 

 swoUen, but more numerous than in the other species, hiding the 

 scales ; terminal half of tail markedly black. A small part of the 

 rump around and above the base of the tail naked. 



Skull of medium size. Large and open posterior palatal vacuities 

 present. 



Hab. Zambesi and Shire Rivers ; Senna and Tette (Peters) ; 

 Zomba and Milanje ( Whyte). 



2. P. KOTTJM^, sp. n. 



Tail much more thinly haired, the hairs not hiding the scales, 

 and more uniformly coloured, brownish abore, rather paler below. 

 Along the middle of the underside there are a number of peculiar 

 broadened bristles, about 2 mm. long, thin basally, thickened at 

 their middle, and tapering terminally to a point. These thickened 

 bristles are mostly white basally and black terminally. Eump 

 largely naked, a space of half :in inch laterally from the tail, the 

 whole of the back of the hams, and a mesial extension halfway 

 along the sacrum being entirely bare, or Mith a thin covering of 

 fine silky white hairs, so fine as to be quite invisible without a 

 lens. 



SkuU very similar to that of P. tetrad aciyliis, but rather smaller 

 and narrower across the brain-case. 



1 P.Z.S. 1890, p. 445. 

 * P.Z.S. 1881, p. 164. 

 3 Saug. Deut«jh-0.-Afr. p. 29 (1895). 



