190 Fretp Museum or Naturat History — Zooéroey, Vor. X. 
on the throat and inguinal region, deeper and generally forming a 
definite ochraceous band across the pectoral region; all the hairs dark 
slaty at bases; feet buffy white, the forefeet with faint traces of dusky, 
the hind feet with the proximal fourth more or less ochraceous; tail 
dusky above, buffy white below. 
Skull rather large and stoutly built, with broad nasals, heavy 
zygomata, and broad teeth; as compared with that of P. darwini,* it is 
slightly larger, with broader nasals and ascending branches of pre- 
maxille; anterior part of zygomata (infraorbital region) decidedly 
heavier; mesopterygoid fossa narrower; teeth broader and heavier; 
incisors especially broad and strong. 
Measurements:— Type: Total length 263; head and body 131; tail 
132; hind foot (c. u.) 28; ear from notch (dry) 22. Skull of type: 
Greatest length 31.6; basilar length 25.8; zygomatic breadth 17; nasals 
12.4X 4.7; diastema 8; palatine foramina 7.6 2.2; upper toothrow 5.6. 
Remarks:— Four specimens of this species were taken by Mr. 
Anderson in the mountains above the Rio Santa. They show but little 
variation and seem to represent a species quite distinct from any previ- 
ously described. Their ochraceous ears and grayish heads suggest 
possible relationship with the Auliscomys group, but taken as a whole 
their characters are those of typical Phyllotis. However, it would per- 
haps not be unfair to look upon the species as a somewhat connecting 
form between Phyllotis and Auliscomys. Comparison of cranial char- 
acters has been made with P. darwini mainly because the skull in that 
species is of approximately the same size; it is obviously not closely 
related. A species which may have real relationship is P. micropus, 
which also has dark under parts and a relatively short tail; but this too 
is well distinguished. 
Auliscomys subg. nov. 
Type, Reithrodon pictus Thomas. 
Characters: — Somewhat intermediate between Euneomys and Phyl- 
lotis; wpper incisors with slight but distinct grooves near the outer edges 
of their anterior surfaces; molariform teeth slightly more hypsodont 
than in Phyllotis and with the division of the anterior lobe of the second 
upper and lower molars persisting throughout a longer period of wear 
so that these teeth in specimens of average age present three outer angles 
instead of two; pattern of tooth crowns with angles much less oblique 
than in Euneomys; maxillary suture in front of infraorbital foramen 
* Specimens from Oroya and Junin, probably representing P. d. posticalis, 
