58 U. 8. P. 11. . EXP. AND SURVEYS ZOOLOGY GENERAL REPORT. 



SCALOPS, Cuvier. 



Scalops, Cur. "Le$ons d'Anat. Comp. I, 1800." 



Qtn CH. Nows elongated, not fringed ; nostrils superior or lateral ; eyes hidden ; tail short ; teeth 36 or 44, the two anterior 

 upper ones unusually large, and somewhat like those of a rodent. 



Feet with the palms very broad ; the claws broad, depressed, and long, five in number. 

 Hind feet ranch narrower than the anterior, though generally of nearly the same length ; the 

 claws Ktibconical, long, and sharp pointed. The toes more or less webbed to the claws. Tail 

 short, naked or hairy. Eyes very small ; sometimes covered by the integument. Ears varying 

 from a pin-hole to 0.10 of an inch in diameter. Snout long, 'depressed, conical, cartilaginous, 

 without any fringe at the extremity ; the nostrils opening at the end of the muzzle, either lat 

 erally or superiorly. 



The teeth vary from 36 to 44, according to the species. The two middle incisor teeth (one 

 on each side) in the upper jaw are very large and broad ; the two next succeeding, on either 

 side, are small ; the next, representing the canine, is a little larger. The premolars vary with 

 the species, from three to four ; the lower incisors from two to three, making the difference in 

 the whole number of 8, (^5). The premolars increase progressively from the canine to the 

 molars. In the lower jaw, the first incisor is very small ; the second is a good deal larger, 

 especially in S. aquations ; the remaining teeth increase progressively in size to the molars. 



The characters of Scalops, as given above, embrace two very distinct types of dentition ; the 

 differences being not only in the number but also in the character of the teeth themselves. 

 Pomel, in a sketch of the geographical distribution of the Insectivora, published in the Bulletin 

 de la Soc. Geologique de France, for 1842, while very properly retaining the name of Scalops 

 for the species with 36 teeth, indicates, without describing, a genus, Scapanus, for those with 

 44. The distinguishing characters will then be as follows : 



Scalops. Teeth 36. Formula : incisors ^, canines l ~, premolars |^, molars !^|, = 20 ; or 

 perhaps more correctly incisors ~, canines ^, premolars ^, molars |~ = ^r= 36 teeth. 

 The two lateral incisors on each side above very small, thread-like, and often deciduous ; the 

 canine large, and fitting into a diastema between the second and third teeth of the lower jaw ; 

 the two anterior molars nearjy quadrate, without any small basal cusp visible on the anterior 

 outline, either externally or internally, (indicated very faintly in the first upper molar.) All the 

 lateral teeth separated by diastemata ; the canine wanting. The second external lower incisor 

 much larger than the first ; canine-like. Tail nearly naked. Nostrils in the obliquely trun 

 cated end of the muzzle, but antero-superior ; not visible from beneath. 



Scapanus. Teeth 44. Formula: incisors ~, canines ~ v premolars J, molars *^, = | = 44. 

 All the teeth of both jaws anterior to the last premolar, (excepting the broad anterior upper 

 incisor,) are of nearly equal size, conical, the upper ones with the points rounded off, and 

 closely resembling the simple teeth of Cetaceans ; the lower more compressed and with the points 

 more .acute. The upper canine is only appreciably larger than the two incisors anterior to it, 

 and the two premolars immediately succeeding. The premolars increase in diameter from first 

 10 Jthird, though of equal Jenjgth ; the fourth is much larger, and triangular in section. The 



