368 IT. 8. P. R. R. EXP. AND SURVEYS ZOOLOGY GENERAL REPORT. 



GEOMYS, Rafinesque. 



Geomys, RAFINESQUE, Amer. Monthly Magazine, II, November, 1817, 45. 



Diplostoma, RAF. IB. (in part ) 



Saccophorus, KOHL, Beitrage, 1820, 65. 



P t eudostoma, SAY, Long's Exped. R. Mts. I, 1823, 406. 



AUD. & BACH. N. Am. Quad. I, 1849. 

 Jscomys, LICHTENSTEIN, Abh. Berl. Akad. for 1822-'23, (1825.) 20. 



BRANTS, Het Geslacht der Muizen, 1827, 23. 



WAGNER, Suppl. Schreber, III, 1843, 380. 



A large groove near the central line of the upper incisor. Skull large and massive ; zygomata thickened. Anterior upper 

 molar with the two lobea elliptical, much elongated transversely and approximated, nearly equal. Middle two with the outlines 

 regularly elliptical. Posterior lower molar sub-elliptical. Ears obsolete. 



a. A second fine groove near the inner edge of upper incisors. Fore feet much larger than the hinder ones. Third claw of 

 hand greatly developed; second claw reaching only to the middle of the fourth. 



6. Only one groove on or near the central line. Fore and hind feet nearly equal. Third claw much developed ; second 

 claw and finger nearly as long as the fourth claw. 



Form of body thick-set, cylindrical ; heaviest anteriorly, especially about the head. There is 

 no indication of a neck ; on the contrary, the thickest portion is at the back part of the head, 

 from which the body tapers gradually to the tail, widening a little across the thighs. The 

 nostrils are small, elliptical, with a papilla above ; they are quite distant apart, situated laterally 

 on each side of a blunt muzzle. This muzzle has a broad furrow down the middle, with 

 a slight ridge at the bottom of the furrow. The muzzle is bounded above by a horizontal 

 furrow having an overhanging ridge, which is coated with short hairs at its upper portion. 

 The upper lip is not cleft, but passes almost directly in a straight or slightly concave line across 

 the bases of the incisors ; the space between this outline and the naked muzzle (almost as high 

 as the muzzle itself) being coated with short hairs. 



The opening of the mouth is quite diminutive, although there is an anterior chamber behind 

 the incisors which narrows behind to the true mouth. The skin lining this chamber (which 

 extends above almost as far back as the molars) is covered with short hair, except, perhaps, just 

 back of the upper incisors, where there is a naked space bounded by a short fold of skin. The 

 lower lip is tumid, quite free, and capable of much motion round the incisors. The upper wall 

 of the cheek pouches begins at a point which forms an equilateral triangle with the end of the 

 upper incisors and the nostril ; it ends about opposite the posterior extremity of the lower side 

 of the lower jaw. The plane of the opening is nearly parallel with the vertebral line. The 

 pouch runs back to the middle of the scapula, and is capable of much distension. It is well 

 clothed with hair on the side next the head ; on the other it is nearly naked with a few scattered 

 hairs. The ears are very rudimentary, represented only by a thickened ridge of skin, narrowest 

 above and widening below. In drying, this ridge disappears almost entirely. The tail is 

 thickened, though tapering somewhat to the tip, which is blunt and naked for about half an 

 inch, and appears to possess some degree of tactile sensibility, as in the opossum. It is hairy, 

 except at the end. 



The upper surfaces of all the feet are covered with short hairs, but they are perfectly smooth 

 and rather tumid below. There is a very large tubercle at the base of the palm, divided by a 

 longitudinal groove which passes round behind the inner smaller portion. From the posterior 



