^i Messrs. Say and Ord on Ncotoma Floridana. 



two exlerioFj and two interior : second Molar with four triairgles, 

 one anterior, two on the exterior side, and a very small one on 

 the interior side : third Molar with four triangles, one anterior, 

 two exterior, and a very minute one anterior. 



Inferior jaw. Incisor qm en ^ pointed at tip : ^r*i Mo^ar with 

 four divisions or triangles, one anterior a little irregular, then 

 one exterior, one interior opposite, and one posterior: second 

 Molar with four triangles, anterior and posterior ones nearly 

 similar in form, and intermediate one opposite to the interior 

 and exterior one : third Molar with two triangles, and an addi- 

 tional very small angle on the inner side of the anterior one. 



Tail hairy : forefeet four toed with an armed rudiment of a 

 fifth toe : hind feet five toed. 



Obseuvations. The grinding surface of the molares differs 

 somewhat from that of the molares of the genus Arvicola^ as will be 

 perceived by our figures ; but the large roots of the grinders con- 

 stitute a character essentially different. The folds of the enamel 

 which mark the sides of the crown, iiiO not descend so low as the 

 edge of the alveolar processes ; in consequence of this conforma- 

 tion, the worn down tooth of an old individual must exhibit insu- 

 lated circles of enamel on the grinding surface. 



This genus must be placed near to Arvicola^ of which it is pro- 

 bable some naturalists may be inclined to consider it a subgenus. 

 N, Floridana. Snout elongated ; eyes and ears very large ; tail 

 longer than the body. 

 Plate X. 



Ears conspicuous, thin, subovate, clothed with such fine hair 

 as io appear naked ; Whiskers long, anterior ones white, the 

 rest black; tail white beneath, dusky above ; its scales so small, 

 and so well concealed with hair, as to be hardly visible ifeet and 

 claws white, the latter short : bodij and upper part of the head 

 clothed in fine fur, of a lead colour, intermixed with yellowish 

 and black hairs, the black predominating on the ridge of the 

 back, and the top of the head, — the yellow at the sides; the 

 lead coloured fur not visible externally : the border of the abdo- 

 men and of the throaty buff colour : base of the claws covered 

 with white hairs. 



