rom “Otro Cerro,’ North-eastern Rioja. 493 
A 
Bulle small, nasals unusually narrow and pointed behind, 
ears and tail short, all as compared with the next species. 
The bulle are about 4 mm. in longitudinal diameter as 
measured along a line parallel with the middle line of the 
skull. Kars as measured by collectors 21 or 22 mm. in 
length. ‘Tail usually 100-110, rarely 115mm. _ In two very 
old specimens, however, nos. 349 and 364,. of whose deter- 
mination I do not feel quite sure, these dimensions are 
exceeded, the ears and tail reaching to lengths normal in 
Ph. ricardulus. 
6. Phyllotis ricardulus, sp. n. 
3. 332, 355, 366, 372; 2. 346, 351, 373. 
Like P. Teena but Pail larver ate. larger ears, and 
longer tail. 
Size about as in tucumanus. General colour above olive- 
grey, varying, as do all the species of PAyllotis, in the extent 
to which buffy is suffused in the colour. Sides, when in 
adult pelage, with a well-marked buffy band running from 
cheeks to base of tail. Under surface soiled grey, the hairs 
very dark slaty basally, broadly washed with whitish or 
buffy whitish. Hars decidedly longer than in  tucumanus, 
but much smaller than in vaccarwm or wolffsohni, their pro- 
ectote blackish, the rest grey. Hands and feet pure white. 
Tail longer and’ more heavily pencilled than in tucumanus, 
its length rarely less than 130 mm.; blackish proximally and 
black terminally above, white below. 
Skull with the nasals not so markedly narrowed behind as 
in éuceumanus. Supraorbital edges sharply square, not ridged. 
Palatal foramina reaching to the level of the first lamina of 
m’. Bulle comparatively large, distinctly larger and more 
fully inflated than in tucumanus, though smaller than in 
vaccarum, their antero-posterior length on a line parallel with 
the middle axis of the skull d9mm.ormore. Molars averaging 
smaller than in tucumanus, though rather variable. 
Dimensions of the type :— 
Head and body 112 mm.; tail 145; hind foot 26; 
ear 23. 
Skull: greatest length 30; condylo-incisive length 27:5 ; 
zygomatic breadth 15°8 ; nasals 12°5; interorbital eee 
4:2 ; breadth of brain-case 14; palatine foramina 7°2 ; post- 
foraminal palate 5°3 ; bull (measured as described above) 
5:1; upper molar series 5. 
Type. Adult female. ‘B.M. -no. 19. 2.7.27. Original 
number 346, Collected 31st August, 1918. 
Although undoubtedly closely allied to Ph. tucumanus, 
this species may be distinguished by its longer ears, its longer 
