188 BULLETIN OF THE 
dark color of the fore leg is separated from that of the upper parts by the fawn- 
colored stripe; that of the hind leg is continuous. Ears conspicuously bor- 
dered with white. The general color of the upper parts is blackish intimately 
grizzled with gray and sandy ; the dark colors predominate and give the gen- 
eral effect on the back, the admixture of sandy increasing on the sides in 
approaching the fawn-colored stripe. The spines are colorless in all their 
grooved portion, the smooth sharp lips being blackish ; these comprise one fifth 
to one fourth of the whole length. The very slender hairs intermixed with the 
spines are similarly colored. The spines are restricted to the upper parts; 
elsewhere the fur is soft, but coarse, and there appears to be no under fur. The 
hairs of the white under parts, and of the fawn-colored stripe, are uniformly 
colored from root to tip. The tail sharply bicolor, blackish above and white 
below, fully haired, the hair completely hiding the scales; the pencil at the 
end is entirely dark-colored and occupies the terminal inch of the vertebra. 
Whiskers partly blackish and partly colorless. Claws nearly colorless, Inci- 
sors yellow. 
“The length of the well-prepared skin (No. 5889, M. C. Z.) is 4.30 inches. 
Tail vertebre the same. Tail with hairs, 4.75. Hind foot, 1.15. Ear, .55 
above notch. 
“ As above stated, this example is of the size of Perognathus fasciatus, which 
it much resembles in general appearance, especially in the conspicuous fawn- 
colored stripe along the sides ; in its long tufted tail it resembles P. pencillatus, 
but is of course generically different from either. The white rim of the ears is 
also a strong mark.” — Coues, MS. 
In 1868, Dr. J. E. Gray (Proc. Zoël. Soc., 1868, pp. 204, 205) described three 
species of Heteromys from Mexico (H. longicaudatus, irroratus, and albolimbatus) 
and one from Honduras (H. melanoleucus), all of which Mr, Alston has re- 
ferred to a single species, together with another (I. adspersus) from Panama 
described by Dr. Peters, in each case from an examination of the types, For 
this species he adopts the name longicaudatus as “the only one of Gray’s names 
which is not absolutely misleading.” In view of this large number of syno- 
nyms it seems presumptuous to take the risk of adding another, although the 
present example does not agree with the characters given by Mr. Alston for 
H. longicaudatus, nor with those of any of the species described by Gray, 
although recalling certain features of two of them. It has, for instance, the 
white-rimmed ears of H. albolimbatus, and “the yellow streak on the side,” or 
* widish interrupted yellow line,” of H. irroratus (which, however, Mr. Al- 
ston says, is merely “a slight tinge of pale fawn along the edge of the darker 
coloring”), except that in the present example it is not interrupted and forms a 
conspicuous feature of the coloration. There is no allusion in any of the de- 
scriptions, nor in Mr. Alston’s diagnosis and remarks, to the conspicuous crest 
of long (.50 to .65 of an inch in length) blackish hairs along the terminal fifth 
of the tail-vertebre, unless it be that the phrase, “short black hairs, which 
are more abundant on the upper part near and at the tip, forming a kind of 
pencil,” in the description of H. albolimbatus, can be so construed, From Mr. 
