JS'ew Species of Quadruped of the Order Rodcniia. 385 



The following are the comparative dimensions of one of the largest 

 specimens of both species.* 



AgaMA CoRNtlTA. " TaPAYAXIN. 



Total length, 3 in. 6 eighths. - Total length, 6 in. 



Length of tail, 1 in. 2 eighths. - Length of tail, 2 in. 

 Breadth of body, 1^ in. - Breadth, varying. 



- Length of longest horn, ^ in. 



The following are the ascertained synonyraes of the animal of 

 Hernandez, viz. 



Tapayaxin Lacertus orbicularis, Hernandez, Nova Plant. Anim. 

 Min, Mexicanorem Hist. p. 327, 328 — (see plate.) 

 Phrynosoma orbicularis, Weigmann, in Isis, 1828, pp. 365-368. 

 Wagler, Icon. Amph. pi. 23. fig. 1. and Nat. Hist. 

 ofAmph. p. 146. Gravenhorst, Acta. Acad. Cses. 

 Leop. Carol. Nat. Cur. vol. xvi. p. ii. 

 Tapaya orbicularis, Cuv. Regne animal, il. p. 37. 

 Agaraa orbicularis, Voigt, Trans, of Cuv. R. A. ii. p. 59. 

 We have seen a specimen of A. orbicularis in the museum of 

 Cincinnati, said to have been obtained from the plains of Missouri. 

 If the statement be correct, we shall have four species of Agama in 

 the United States, viz. : A. Cornuta, A. Collaris, A. Douglassii ; 

 together with the first named species— vld. Harl. Med. and Phys. 

 Researches, for figures of the others. 



Art. XXIV. — Description of a new species of (Quadruped, of the 

 order Rodentia, inhabiting the United States } by R. Harlan, 

 M. D. 



Mus palustris. 



Characters. — Body rather elongated, color above of a ferruginous 

 brown ; beneath, grayish white, the hairs being plumbeous at base : 

 legs small : tail long : ears half the length of the head. 



Description. — The color above resembling nearly that of the com- 

 mon Norway rat ; beneath, grayish white ; ears of moderate size^ 

 anterior borders slightly inverted, sparsely hairy within and without : 



* The specimen figured by Wagler, was ralher larger, viz. total length 7 in, ; 

 tail 2^ in. 



Vol. XXXI.— No. 2. 49 



