On new South- American Rolents, 503 



Dimensions of tlie type (measiirod in flesli) : — 



Head and body 92 mm. ; tail 12-5; hind foot 16; ear 10. 



Skull: {greatest len<jrth 27'2 ; basal len,"jtli 24*4; greatest 

 breadth 15; nasals 11x28; interorbital breadth 4"6; 

 breadth of biain-case ir2 ; palatal Icnf^th 14 3; combined 

 len<;lh of three molarlform teeth 4-4; breadth across outer 

 corners of m^ S'5. 



Type. Adult female. Original number 01. Collected 

 15th June, 1910. 



This pretty little species has a considerable external 

 resemblance to the M. marica of Merida, Venezuela, but is 

 probably really most nearly allied to M. mlcrotarsus, from 

 which it differs by its paler colour and rudimentary post- 

 orbital processes. The variation in the coloration of the 

 belly-hairs is unusual in this group, 



"Catita pequeiia."— £". S. 



LVII. — Fonr neio South- American Rodents. 

 By Oldfield Thomas. 



(Published by permission of the Trustees of the British Museum.) 



Sciurus {Mlcrosciurus) similis fusculus, subsp. n. 



A lowland race of S. similis*. 



All characters as in similis, except that the olivaceous tone 

 of the upper surface is replaced by blackish brown (darker 

 than " vandyke-brown "), the fine rings on the hairs,. buffy in 

 similis, reduced in prominence and tending towards tawny. 

 On the face and sides this alteration from buffy to tawny or 

 tawny ochraceous is particularly evident. Colour of chest 

 also rather " tawny ochraceous " than '' ochraceous," as it is 

 in similis. 



Dimensions of the type (measured in the fles'i) : — 



Head and body 126 mm. ; tail 108 ; hind foot (s. u.) 33 ; 

 ear 13*5. 



Ilab. Choc6, W. Colombia. Tyi)e from Juntas^ Rio San 

 Juan. Alt. 400'. 



Tt/pc. Adult male. B.M. no. 10. 7, 16. 2. Original 

 number 141. Collected 27th February, I'JO!*, by Merv>°i G. 

 Pahner. Two specimens. 



* Nelson, Bull. Am. Mas. N. H. xii. p. 78 (1899), 



