252 Mr. O. Thomas on 



but its skull and teetL are so much smaller that it cannot be 

 the same species. 



Proechimys ihering'i, sp. n. 



Allied to P. alhispinus, Geoff. 



Size rather larger than in P. alhispinus. Coat intermixed 

 with spines througliout, quite to the base of the tail; spines 

 of -back about 20-22 mm. in length by ^ mm. broad, pale 

 greyish basally, with black tips, a certain number on the 

 rump and flanks, as in alhixpinus^ wholly white. General 

 colour more rufous brown than in alhispinus, but the type 

 has been skinned out ot" spirit and may be somewhat dis- 

 coloured. Under surface wholly white. Hands and feet 

 white. Tail brown above, strongly contrasted white below. 

 Skull decidedly longer than that of alhispinus. Muzzle 

 and frontal region convex mesially instead of flat. Supra- 

 orbital ridges little developed, very much less than in alhi- 

 sjnnus, and not extending on to the parietals. Zygomata 

 broad vertically, the ridge crossing their outer surface almost 

 obsolete. Palatal foramina short, as in albispimis, their 

 posterior lips less develo])ed. Posterior palatal edge at level 

 of middle of m^. Hamular processes of medium breadth. 

 Bulla} small and low. 



Dimensions of the type (measured on a spirit-specimen 

 before skinning) : — 



Head and body 200 mm. ; tail 183 ; hind foot 45 ; 

 ear 24. 



Skull: greatest length 53; condylo-incisive length 43; 

 zygomatic breadth 27; nas;ils20; interorbital breadth 12*3 ; 

 palatilar length 18 ; palatal foramina 3"8 ; upper tooth- 

 series 9. 



JIah. Island of Sao Scbastiao, off Sao Paulo, Brazil. 

 Type. Adult male. B.M. no. 2. 8. 25. 5. Presented by 

 the Sao Paulo Museum through Dr. Hermann Ihering. Two 

 specimens. 



I had long supposed these specimens to be albt'sjv'uus, 

 descril)ed from Bahia, but a study of a series of tiiat animal 

 obtained by Mr. A. Robert at Lamarao, in that State, shows 

 that the Sao Sebastiao form is readily distinguishable by the 

 cranial characters above detailed. 



I have named this distinct species in honour of the sender 

 of the specimens, Dr. H. von Ihering, Director of the 

 Sao Paulo JMuseum, to whom science is indebted for much 

 valuable work on the zoology of Brazil, and to whom also 

 the British Museum owes many interesting specimens. 



