from Iti<i:ll ami Kcuadoi'. li>.'> 



I'riiechiinya oris, sp. ii. 



Most np«irly allied to P. cayfnnenHts and /'. Rnhertl. 



0<'noral proportions aliont as in P. c n/ennens/'s. Spines of 

 liark more restricted in tlu'ir di^frilnition than in that spooies, 

 tlie posterior l)aek for ni-arlv a third of its l('nj];tli IxMiig 

 spineless ; thi;;hs, Hards'*, and nape* also j)ructically without 

 spines. iSpines of back about 18 mm. hmg by 07 mm. 

 broad. Lower belly and inner sides of fornarms and thi;^lH 

 nearly naked. (Jeneral colour above dark tawny brown, 

 lined with blackish, the soft-haired rumu more rufous; head, 

 sides, arms, and hga grt'yish brnwn. In /*. rn'/eriucnsis tin; 

 general colour is darker, the rump browtush, and the back 

 of the hind legs heavily blackened. Hands and feet dull 

 whitish, without special markings. Tail large-sciled, thiidy 

 liaired, brown above, whitish below. 



fSkull very like that of P. coi/ennensh, but rather more 

 slender. Interparietal longer antero-posteriorly. Anterior 

 edge of mal.ir forming a long, sharp, forwardly projecting 

 angle at its junction with the maxillary, the corresponding 

 line in P. cayennensis being short and obtuse. Palatal 

 foramina will open mesially, but narrowing rapidly behind 

 almost to a point, with little trace of such raised edges as in 

 P. cnyf-nvensis form two parallel open gutters behind. Base 

 of skull l)elweeii bulla? narrower than in cnyennensis. 



"JVeth as in P. cnyennensis, tiie upper ones all simply and 

 uniformly quadrilaminate. 



Dimensions of the type (measured by Mr. R'>bert in tiie 

 flesh) :— 



Head and body 245 mm. ; tail 17-4; hind fwot (s. u.) 4ij ; 

 ear 21. 



Skidl : greatest length 58 ; basilar length 41 ; zygomatic 

 breadth 26; nasals 21'5; interorbital breadth 12; breadth 

 across parietal ridges 21 ; palate length 195; diastema 11*8; 

 palatal lorannina 7x32; length of upper tooth-.series 82. 



J/ai>. Jgarai e-Assu, near Pard. All. 50 m. 



Jy/je, Old male. B.M. no 4. 7. 4. 78. Original number 

 1818. Collected Gth .March, l'J04, by Alplumse Itobert. 

 ►Seventeen specimens. 



This spiny rat differs from J', oiyennenais, of which the 

 British Museum contains four topotypes obtained by Mr. G. K. 

 (/lierrie, by its more rufous colour, especially its much more 

 reddish rump and hind limbs, by the lesser spininess of its 

 posterior back, by tiie nakedness of its inguinal region, and 

 by the cranial characteis above detailed. 



Another allied species is P. /{o/ierti, T!ios., of S. Minas 



