MAMMALS—TALPIDAE-SCALOPS AQUATICUS. 
59 
penultimate upper molar is trapezoidal, nearly triangular in cross section, instead of subquad¬ 
rate ; the one anterior to it-is also trapezoidal, instead of lozenge shaped. Viewed externally, 
there is a small acute lobe on the anterior edge uf the last premolar, and all the molars, close 
to the base of the crown ; and there is a similar lobe on the inner edge of the corresponding teeth 
of the lower jaw. The molars are in close contact; the teeth anterior to these, in the upper jaw, 
are separated by diastemata. The lower incisors are of nearly equal size, the second not larger 
than the first. The nostrils are near the end of the muzzle, either lateral or superior. The 
tail is more or less hairy. 
The chief differences in dentition between Scalops and Scapanus, then, are in the greater num¬ 
ber of teeth in the latter ; the greater permanence and more uniform size of the incisors and 
premolars ; the anterior basal fang to the last premolar and the molars, and the different shape 
of the molars. Other distinctions might be enumerated, but at the risk of pursuing the subject 
into too great detail for my present purpose. 
To the restricted genus Scalops belong at present three species : S. aquaticus, inhabiting the 
whole eastern portion of the United States, from Massachusetts to Florida, and west to Missis¬ 
sippi and Alabama; S. argentatus, a prairie species, ranging from Michigan, through northern 
Ohio, Illinois, Missouri, northern Louisiana, Arkansas, Kansas, and Nebraska, as far at least 
as the Upper Missouri; and S. latimanus, found in Mexico, and stated also to occur in Texas. 
No specimens of the latter have come under my notice. 
Of Scapanus there are two very distinct species, one found in Massachusetts, New York, and 
northern Ohio, (/S', breweri,) the other, ( S . townsendii,) in Washington and Oregon Territories. 
Whether the California mole, called Scalops californicus by Ayres, be really distinct from S. 
townsendii can only be shown by additional specimens ; if the same, the range of S. townsendii 
will extend from Puget Sound to San Francisco. 
The European analogue to the American mole, though so similar in mere external form, yet 
differs by so many striking peculiarities of dentition as to render it a matter of very great sur¬ 
prise that authors at this late day should have thrown both into the same genus. To illustrate 
the differences, I subjoin the chief characters of Talpa. 
Talpa. —Teeth 44 in number. Formula: incisors canines premolars molars ~ 
= H = 44. The three incisors on each side of the upper jaw are very small and uniform in 
size, (except in T. coeca , where the middle ones are rather largest,) then succeeds a well devel¬ 
oped canine, curved, compressed, and trenchant, implanted by two roots, followed by three 
compressed premolars of similar size and shape, with two fangs each ; then a fourth premolar, 
trihedral with three (?) roots. All the premolars of the lower jaw have double roots, the 
anterior largest, simulating a canine ; the canine itself separated from the premolar by a dias¬ 
tema, and not distinguishable from the incisors in shape. 
The nostrils are strictly terminal, and open antero-inferiorly, so as to be visible from below 
and not from above, the reverse of what is the case in the American moles. 
It will thus be seen that Talpa differs from Scalops in the small size of the anterior upper 
incisors, the large upper canine, and the double roots to all the premolars, except the last, which 
has three. In Scalops the premolars, except perhaps the last, have simple roots only. In 
Talpa the nostrils are terminal, and antero-inferior. Condylura agrees with Talpa in the double 
roots to the premolars. 
