M. Du Chaillu' s ' Adventures in Equatorial Africa.' 63 



habitat, are sufficient to constitute this the representative of a di- 

 stinct genus, for which he proposes the name of Potamogale, prefer- 

 ring, however, " to wait until he can procure the skull and skeleton ; 

 therefore he places it in the genus Cynogale, to which it certainly 

 bears a close resemblance." He further says, " the teeth resemble 

 those of the above genus of Gray." 



I may state that the animal does not appear to me to bear any 

 relation to the genus Cynogale ; and, from the form of the feet and 

 tail, I suspect that it is a Glirine animal, and much more nearly 

 allied to Fiber, Hydromys, or Castor than to any ferine genus. As 

 M. Du Chaillu has not characterized his genus Potamogale, and has 

 given such an erroneous description of the feet of the specimen that 

 no one could recognize it, I do not think that his name has any claim 

 to be retained, especially as it implies what appears to me to be a 

 very doubtful affinity to the Musteline animal. 



I therefore propose, as the feet differ essentially from any other 

 genus that has come under my observation (though the peculiarity 

 has escaped M. Du Chaillu and the naturalist that helped him in the 

 preparation of his maiden zoological paper), and as I believe that it is 

 necessary to form a genus for it, to call it Mystomys ; and it may 

 be thus characterized until the skull and teeth are discovered : — 



Whiskers elongate, rigid. Feet small, rather slender ; toes 5'5, com- 

 pressed, elongate, not webbed, free, except the two middle toes of 

 the hind feet, which are united together to the claws ; claws com- 

 pressed, curved. Tail short, stout, thick, compressed, covered with 

 short adpressed hairs, except at the base and along the middle of the 

 upper edge, where it is covered with close, soft, erect fur. The fur is 

 soft, with flattened, elongated, striated hair, which is produced beyond 

 the under-fur as in Castor and Fiber. 



Mystomys vefox= Cynogale velox, Du Chaillu. 



M. Du Chaillu describes the feet and tail as follows ; and this is a 

 good specimen of his qualifications as a scientific zoologist: — "The ex- 

 tremities small, the first joint enclosed within the skin of the body (!) ; 

 feet five-toed, plantigrade behind ; soles bare ; claws curved and 

 sharp ; fore claws (!) very slightly, if at all, webbed ; hind claws (!) 

 partially webbed, and the external border of the tarsus fringed with 

 a membrane ; tail stout, compressed laterally, and terminal three- 

 fourths sharp above, and at the end below terminating in a point." 



Sciurus Nordhoffii and Sciurus eborivorus. — These are only slight 

 varieties of Sciurus Stangeri of Waterhouse ; they both have the 

 characteristic black streak behind the ear. I may observe that the 

 Common Rat eats ivory. 



Sciurus Wilsonii. — This appears to be Sciurus mutabilis of Peters; 

 it is very nearly allied to Sciurus Stangeri, if indeed it be distinct 

 from that species, only wanting the black streak above referred to ; 

 but Squirrels are exceedingly variable in colour, even when collected 

 at the same time from the same locality. 



Sciurus subalbidus is Sciurus rufobrachium, Waterhouse. 



Sciurus rubripes is Sciurus pyrrhopus, F. Cuvier. M. Du Chaillu's 

 specimens are brighter-bay on the head and legs than the specimen 



