Petrodromus and Rhynchocyon. 367 



The following new forms also appear to need description : — 



Petrodromus robustus, sp. n. 



Similar to venustus, but larger and with more powerful 

 muzzle and incisors. 



Size rather greater than in venustus, the feet stouter. 

 Colour about as in that animal, though not so pale as in the 

 most extreme specimens ; feet similarly whitish instead of 

 brown as in tetradaotylus. Under suiface of type white 

 almost without huffy suffusion ; the hairs slaty at base. A 

 patch on the chest drabby, but this may be either glandular 

 or artificial, like the chest-staining found in many African 

 small mammals, and often mistaken by ignorant workers for 

 a natural character. Tail well-haired, black except for its 

 basal third below, where it is dull whitish. 



Skull very stout and heavy, larger than iu any true Petro- 

 dromus, and only equalled by that of P. (Cercoctenus) sultan. 

 The muzzle is long and broadened in front, where it contains 

 the large anterior incisors, not evenly tapering forwards as is 

 usual. Nasals also broader. Palate with the large vacuities 

 characteristic of true Petrodromus. Parapterygoid fossae very 

 broad, the breadth across the pterygoids 10 mm., a breadth 

 only approached in other species when long lateral spines are 

 developed, which is not the case here. The lines of the outer 

 edges of the ectopterygoids, if produced forwards, meet at an 

 angle of about 55°, while this angle is ordinarily about 40° in 

 tetradactylus and 43°— 47° in venustus, but, of course, there is 

 a good deal of variation in individual cases. 



Anterior ineisors conspicuously larger than in any other of 

 the allied species, only equalled in length, though not in thick- 

 ness, by those of P. (Cercoctenus) sultan ; their length 5 mm. 

 and their greatest diameter 2'2 ; their height fully double 

 that of i 3 and the canine. Other teeth broad and stout ; p d as 

 broad posteriorly as anteriorly. 



Dimensions of the type (measured in flesh by collector) : — 



Head and body 193 mm. ; tail 178 ; hind foot 57*5 

 (56*5 dry); ear 38. 



Skull: greatest length 57; condylo-basal length 53'2; 



with venustus. In the measurement.'? given it is not clear whether " bas. 

 leng." means basal or basilar length, while it it clear that " molar series " 

 includes premolars as well as molars. 



I regret to have to recur to the character of Mr. Roberts's mammal 

 work, but accident having necessitated my working on the same things 

 from the same region, 1 should not he doin^ my duty if I took the easy 

 course and refrained from commenting on the harm such work 13 lik?ly 

 to do to the mammalogy of the countries concerned. 



