228 On a neio Species o/Ctenomjs. 



lieavier throughout . Nasals and interorbital region broader 

 and the ktter more heavily ridged. Palatal foramina much 

 wider and more open, half as broad again as in the allied 

 species. Bullae considerably larger and more inflated. 



Dimensions of the type (measured in the flesh) : 



Head and body 276 millim. ; tail 203; hind foot s u 43 

 c. u. 47-5 ; ear 24, J • • . 



Skull : greatest length 57-5 ; basilar length (c.) 42 ; 

 greatest breadth 29-5; nasals 19-3x7; interorbital breadth 

 13-2; palate length 2()-4 ; palatal foramina 7-1 X 5-4; dia- 

 stema 11 ; length of bulla lo'3; upper molar series 9. ' 

 Ilah. Sapucay, Paraguay. 



Type. Old male. Original number 851. Collected 2nd 

 Se]itember, 1902, by Mr. W. Foster. Four specimens. 

 " Trapped among tumbled rocks." 



The discovery by Mr. Foster of this Paraguayan species of 

 Thrichomys is an exceedingly interesting one, as the genus is 

 excessively rare, and has been recorded hitherto from one 

 locality only, Lagoa Santa, where Lund obtained his "Echimys 

 cp( reoi'des,'' afterwards renamed by him Neloinys antricola 

 imder Avhich term it is described in Winge's ' Rodents of 

 Lagoa Santa.' 



The British Museum is indebted to the autliorities at 

 Copenhagen for one of the specimens described bv Dr. Wino-e 

 and I have therefore been able to make a direct comparis^oii 

 between the two forms. 



Azar(e, sp. n. 



Size medium, about as in G. tucumanus and wendocmus. 

 General colour uniform brown (between "wood-brown" and 

 fawn-colour) above and pale buffy below, without darker 

 markings on the upper surface or white patches below the 

 only variation being that the top of the muzzle is slightly 

 darker than the rest. '^ ^ 



Skull in general shape most like that of C. mendocinus 

 coriiparatively narrow and slender, not flattened and squared 

 as HI C. tucumanus, or thickened throughout as in C. Perrensi. 

 Nasals short and narrow. Literorbital region ridged, wi'tli 

 rudimentary postorbital processes; parietal ridges more m'arked 

 than in the allied species. Zygomata sloped backwards 

 gradually to the broadest point, instead of being evenly 

 rounded as in mendocinus, or square-shouldered as in tucu- 

 wanvs. Palatal notch level with the hinder edge of ni^ 

 instead of with its centre as is more usual. BiTllte much 

 more swollen than in either of the other species mentioned 



