186 The American Naturalist oe 
cess erect, abruptly recurved near the blunt tip, anterior width of 
nasals nearly twice that of posterior width ; a broad supraorbital fur- 
row laterally borders the brain case from the lachrymals to the mas- 
toid side of parietals, audital bullae separated anteriorly by full width 
of basi-sphenoid, molariform dentition as in P. paradorus. 
Measurements—(from mounted specimen); length of head and body 
145; hind foot (shrunken), 27; ear from crown, 6. 
Skull.—total length (approximate) .35; tip of nasals to interparie 
tal 28.4; base of incisor to anterior tip of audital bullae 18; zygo- 
matic width (at outer bases of squamosal process of malar) 17.5; in- 
terorbital constriction 8.8; length of nasals 14; nasal width (near tip) 
4.2; nasal width (near base) 2.2; interparietal width 8.2; crown 
length of upper and lower molar series 4.6; length of median parie- 
tal suture 5; greatest parietal length (masto-squamosal) 10; length of 
mandible (inner base of incisors to condyle) 17.4; height of coro 
noid process from angle 8; greatest depth of cranium 11. 
The specimen from which the above description is taken was col- 
lected by J. K. Townsend during his memorable Rocky Mountam 
journey nearly sixty years-ago. It has been exhibited in the museum 
of the Academy during the greater part of that period and has lost its 
tail in the service. The locality given on the present label is only ap- 
proximate, if correct at all, as an earlier entry of the specimen (prob- 
ably copied from the original one) in the catalogue gives the epee 
as “694, Thomomys rufescens, yg., J. K. Townsend, Columbia Rivet 
This name was, a long while ago, altered to “ Perognathus fasciatus, 
as the museum label now stands. Probably the person making the last 
identification changed the given habitat to “ Rocky Mountains” to 8 
cord with the habitat assigned to fasciatus by Baird. The specim® 
was probably taken east of the 34th meridan and south of the 43rd 
parallel, in Nebraska or Wyoming. It is not impossible that 1t se 
from a more western region. Its differentiation from its nearest me 
P. paradoxus, indicates a different faunal habitat from that occup! 
by the latter. Dr. Townsend makes no mention of the genus Paw 
nathus in his list of the mammals observed during bis joun 
does Dr. Bachman, in his supplementary list of novelties publish that 
the Journal of the Academy of Natural Sciences. It is possible t 
the specimen, owing to its mutilated (tailless) condition and being P 
in alcohol, was hastily overlooked, or classed as a young Geomys 
catalogue entry implies this), and later on it was mounted as e 
The specimen is over-stuffed, but does not appear unduly st j iti : 
laterally. From its appearance and the dimensions of its sku 
