MAMMALS-TALPIDAE—SCALOPS ARGENTATUS. 
63 
SCALOPS ARGENTATUS. 
Silver or Prairie Mole. 
Scalops argentatus, Aud. & Bach. Jour. Acad. Nat. Sc. Phila. VIII, 11 ,1842, 292.—Ib. N. A. Quad. Ill, 1853,252 ; 
pi. cl, f. 4. 
Wagner, in Wiegm. Archiv, 1843, ii, 31.— Ib. Suppl. Schreb. V, 1855, 573. 
Sp. Ch. —Larger than S. aquations. Teeth 36. Eyes and ears very minute, the former covered by the integument. Nostrils 
antero-superior. Palms scarcely broader than long; tail nearly naked. Color silvery plumbeous. 
This species is very similar to the S. aquations , and smaller specimens are with difficulty 
distinguishable from the latter ; indeed, it may he a question whether the two can with entire 
propriety he separated. The combination of the larger size, more silvery color, and more 
western locality, may, however, substantiate the claim of S. argentatus to a separate place. 
The muzzle is elongated and depressed, the nostrils opening on its antero-superior truncation, 
much as in 8. aquations, hut rather more superior. The anterior face of the upper incisor is a 
little anterior to a point midway between the eye and the tip of the nose. The eye is visible 
as a small bluish speck through the integument, which is not pierced even by a pin-hole aper¬ 
ture, as in 8. aquations . It is placed a little behind the posterior angle of the jaws. The ear 
is represented only by a circular meatus, about the twenty-fifth of an inch in diameter. 
The palms are very large, with the claws but little longer than broad. The hind feet are 
about as long as the anterior ones, but much narrower. The amount of webbing to the feet is 
much as in 8. aquations. 
The general color of this species is a' light silvery plumbeous brown, not very dissimilar to 
that of freshly cut lead. The under parts are a little lighter, especially just back of the arms ; 
a more brownish tint is usually imparted by immersion in alcohol. The prevailing color of the 
feet and tail is white, the latter rather more densely hairy than in the aquaticus, as well as 
longer. 
The Scalops argentatus is sufficiently distinct in its characters to require comparisons only 
with S. aquaticus. The size is much larger, the general proportions similar. The nostrils are 
more superior; the head more slender ; the eye is entirely covered by the integument, which 
extends over the ball, instead of being pierced by an orbital opening. The ear is a little larger. 
The color is much more silvery in its lustre, without any brown. 
The difference in the size of those species is very appreciable in the skulls, of which I subjoin 
the comparative dimensions of the largest specimens in the collection of each. 
The skull exhibits the dentition of 8. aquaticus in having 36 teeth ; or, according to the 
determination of Owen, incisors^, canines ~, premolars molars In the upper jaw 
the anterior incisor is very large and rodent-like ; the two lateral on either side are very small 
and thread-like, and quite deciduous. The canine is moderately thick and prismatic ; the three 
premolars are similarly shaped, and increase successively from first to third; the anterior 
smaller, the middle larger than the canine. All the teeth in the jaws are separated by 
diastemata. 
By the decadence of the small lateral incisors, the number of teeth may be reduced to 34 or 
32. The anterior lower incisor is also very small, and sometimes wanting, making the teeth 
30 in number. 
