494 Mr. O. Thomas on small Mammals 
and more heavily tufted tail, and its larger bulla. Comment 
has already been made on the number of species, superficially 
resembling each other, which live in this region, and the 
occurrence of these two closely allied Pericotes in the same 
locality is very remarkable. But it has a parallel in Hurope, 
in the relationship to each other of Apodemus sylvaticus aud 
A, flavicollis. 
These latter, however, are inclined to segregate themselves 
from each other locally, and it is not improbable that a closer 
study of the actual places where the two Pericotes are found 
will similarly show that they also are not both to be caught 
absolutely on the same ground. 
7. Graomys cachinus, Allen. 
3. 321, 323, 350, 378. 
[In naming these specimens I have re-examined the an- 
determined series referred to in my Chumbicha paper, which 
series I then supposed to belong to but a single species. 
To my surprise I now find that those specimens belong to 
no less than three species—large, middle, and small,—distin- 
guishable almost entirely by size, though, as is not unusual 
in such cases, the development of ears, tail, and tail-tufts are 
in proportion to the general size, the larger species being 
finer animals throughout, with more handsomely tufted tails. 
There are no specimens of a size to make determination 
difficult, and the series of each of the three species contains 
examples with fully worn teeth. The largest species, G. ca- 
chinus, has a skull-length of 33°5-35 mm. Following this 
we have 
7 EA 
Graomys medius, sp. n. 
Size less than in G. cachinus, greater than in the next 
species. Oolour about as in cachinus, but there is rather less 
development of the buffy band along the sides. Under 
surface white, the hairs either wholly white or slaty at base, 
this character proving to be absolutely variable in all these 
species of Graomys. ‘Tail rather shorter and less tufted than 
in cachinus. 
Skull in all ways less developed than in cachinus, smaller, 
with shorter nasals, supraorbital edges sharply angular, but 
with less distinct beads than in cachinus ; bulle smaller. 
Dimensions of the type :— 
Head and body 124 mm.; tail 150; hind foot 27; 
ear 25. 
