f)88 ^Ir. O. Tlioma-? on new 



point ; greyish basally, black terminally. Fit'th Uiiiil toe, 

 without claw, reachini:; just to the level of the front of the 

 pad at the base of the third and f)arth dibits. Mammse 6, 

 two pairs high up on the sides between the limbs, one pair 

 in the inguinal region. 



Skull less ridged than that of P. cayennenais, more heavily 

 built than that of P. oris, with a broader muzzle, the forehead 

 convex niesially, the profile evenly convex to the middle o( 

 the l)rain-case, then strongly declining backwards, sii|)ra- 

 orbital ridges not strongly developed and not continued 

 backwards past the fronto-parietal suture, the surface of the 

 parietals smooth and un ridged. iMalars slenderer and less 

 high than in P. oris. Palatal foramina short, ending 4 mm. 

 in front of the molars, jiarallel-sided, the edges produced 

 backwards as two ]jarallel ridges enclosing the area immedi- 

 ately behind the foramina, this area being at a lower level 

 than the rest of the palate ; septum comparatively broad. 

 Posterior palatal notch penetrating to the level of the hinder 

 edge of in^. Pterygoids narrow, little spatulate. Bullae of 

 medium develoj)nient. 



Cheek-teetli of normal size and structure, the |)remol:ir and 

 last molar each with four, m^ and m^ each with an indication 

 of five lamiiise. In the lower jaw the premolar appears to 

 have five lamina} and the molars four each. In P. oris the 

 teeth throughout, upper and lower, have four laminae each. 

 ]n P. cayennensis the upj)er all have four lamina?, but the 

 lower premolar is as in P. Goeldii. 



Dimensions of the type (measured on thespirit-specimen): — 

 Head and body 223 mm ; tail (lost) ; hind foot (s. u.) 49; 

 ear 20. 



Skull : greatest length 5G ; basilar length 40 ; zygomatic 

 breadth 27-5; nasals 21x6-5; interorbital breadth 13; 

 mastoid breadth 20"5 ; palate length from henselion 19-3; 

 diastema 12*5; palatal foramina 5x3; length of upper 

 check-tooth series 9'8. 



Ilab. Santarem, Lower Amazon. 



Type. Adult female. B.M. no. 5. 1. 25. 6. Presented by 

 Dr. E. A. Goeldi, after whom the species is named. 



The members of the genus Proechiniys being only distin- 

 guishable l)y tlieir cranial characters, I have ventured to 

 describe this spiny rat in s])ite of its apparent discoloration 

 and the tailless condition of the type. The skull is readily 

 distinguishable from that of both P. oris and the Guianan 

 species P. cayennensis by its peculiar jjalatal foramina, even 

 it the differences in the number of the molar lamime prove 

 to disappear on the examination of further specimens. 



