lirush-ttiiUil Porctipine of Central Africa. 89 



fine skull from Sierra Leone, collected lonp^ aj^o by Mr. T. 

 AViiittielil, but only recently rendered available for comparison. 



The additional material shows, as is not surprisini^, that 

 Emin's specimens, while excessively like A.africana in their 

 external appearance, differ so much in cranial characters as 

 to necessitate their specific distinction. 



The species may be called 



Atherura centralis^ sp. n. 



Size, colour, and other external characters very much as in 

 A. africaiuiy excejit that the spines are rather more fimbriatiid, 

 and those of the sides are more frequently tipped with white. 



Skull longer and slenderer, with a flatter, less inflated, and 

 narrower frontal region and better defined postorbital pro- 

 cesses. Anteorbital foramina higher than broa<l, the converse 

 being the case in A. africana] posterior edge of the base 

 forming their lower boundary level with or in front of the 

 front edge of the anterior cheek-tooth, wliether mp.'^ or 

 p.*' ; posterior edge of palate level with the middle of the last 

 molar in place, whether vi."^ or »j,', according to age. 



Teeth remarkably small and delicate, the length of the 

 upper molar series scarcely more than half the diastema, wiiile 

 in the allied species this measurement is about two thirds of 

 the diastema. The small size of the teeth is, of course, the 

 reason for the relatively different position of />.* and the ante- 

 rior zygoma-root. 



Dimensions of the type, marked by Emin as a male (in 

 skin) : — 



Head and body (c.) 500 millim. ; (tail imperfect) ; hind 

 foot GO. 



Skull : basal length 86, basilar length from henselion 78 ; 

 greatest breadth 46 ; nasals, length 28 ; interorbital breadth 

 26'8 ; intertemporal breadth 2A'o ; anteorbital foramen, 

 height 10, width 8, distance between most distant points of 

 the two foramina 35; palate length from henselion 4r7 ; 

 diastema 27'7 ; upper molar series (crowns) 15'3. Length of 

 lower jaw, bone only, 59; condyle to angle 21'6; length of 

 lower molar series 16*8. 



Hab. Alonbuttu, Central Africa. Coll. Dr. Emin Pasha. 



Type: B.M. 87.12.1.98. 



Tiie main cause for distinguishing the Central- from the 

 West-African Atherura lies in the extremely small sIzj of the 

 molar teeih, a characteristic equally observable at all ages. 

 Tliis latter is a ])oint which has to be especially noticed in 

 studying the teeth of porcupines, owing to the peculiar manner 

 in which wear affects the size of the teeth. 



