60 U. Ss. P. R. R. EXP. AND SURVEYS—ZOOLOGY—GENERAL REPORT. 
Measurements. (Taken from dry skins.) 
361. 621. 
Inches. | Lines. Inches. Lines. 
pre apse a 
Nose toirootiof tala" 2-22 oon eae e a ae eeen= 6 ala jer 
Tail from root to end of vertebrae.--.__--_---- 1 4 ie 3 
Hukediportin mses laid 28 eat 4 eeeee ts ib dled 1 1 
Arm, forefoot to end of claws__-_----.-.-----|-------- 11 ae a 9 
Tongestsclaw, Of arm 2-2-2 peo ess of ee) ee 3h 
Leg, bindfoot from heel to end of claws .------/-------- Ey lecoenace 9 
ONES Cla wiOP Nel ae mee aoe ee es een 2 eee ae 13 
Denpth’ Gl paln..sacees nae e woe eae eee ea ie e||Sectence 53 
Breadth /of palmee ss oss- sae ese ae ee phe SAA LS ee 6 
ength/of skhull/--2-=- =~ - 25 Soe Seas 1 Th 1 3 
| 
Description. of a specimen, No. 2212, in alcohol.—General form that of S. aguaticus, but larger. 
Muzzle long, depressed, truncate at tip; naked for most of that portion anterior to the incisors, 
or with scattered hairs. The nostrils open antero-superiorly, on a plane oblique to the axis of 
the muzzle of about 45°; they are, however, partly visible from the side ; much more distinctly 
so from above and theend. There is a smooth bulb or gland at the end ; the rest of this muzzle, 
however, is corrugated ; the wrinkles on the lower surface are oblique to the median furrow, 
and those on either side are parallel to each other. 
The eye, though very minute, is not covered by an extension of the skin of the body, as in 
S. breweri, but is open to the air; the orbit, however, is not larger than a pin-hole. It is situ- 
ated so far back that the posterior angle of the mouth falls about midway between the eye and 
the upper anterior incisor. 
The meatus of the ear is very small and circular, about one-twentieth of an inch in diameter ; 
there is no external ear. The centre of the meatus is about midway between the eye and the 
occiput. 
The palms are very large, and broader than long, exclusive of the claws. These are very 
large and fossorial ; the upper surfaces of the feet are very thinly covered with hair; beneath 
they are entirely naked. The tail is about as long as the skull; it tapers gently to a rather 
acute tip, and is scantily beset with rather long hairs, which scarcely take off the appearance 
of nakedness. 
The nostrils of this species are more superior than in S. brewer, the palms are proportionally 
larger and broader, The tail is more acute, and less clothed with hair. The posterior outline 
of the palm is much less acute, being almost straight, and rounded off at the corners, resem- 
bling the longer outline of an ellipse rather than the shorter, as in S. breweri. The nostrils of 
S. aquaticus are quite similar in their position to those of S. townsendii. 
In specimens from Petaluma, in excellent preservation, the muzzle is much broader and more 
abruptly truncate, although the nostrils are as described. ‘he nostrils are crescentic; the 
concavity superior; their anterior extremities approach each other very closely ; they appear 
rather more terminal than in northern specimens. The size is less; the palms appear propor- 
