RODENTIA ARVICOLINAE FIBER ZIBETHICUS. 561 



FIBER ZIBETHICUS. 



Musk Rat. 



Castor zibethicus, LINN. Syst. Nat. I, 1766, 79. 

 ERXLEBEN, Syst. 1777, 444. 

 BODDAERT, El. Anim. I, 1784, 166. 

 PALLAS, Zoog. Rosso- Asiat. I, 144. 

 JUus zibethicus, GMELIN, Syst. Nat. I, 1788, 125. 



SCIIREBER, Saugt. IV, 1792, 638; tab. clxxvi. (Ondatra in text.) 

 SHAW, Gen. Zool. Mamm. II, 1801, 44 ; pi. cxxix. 

 Myocastor zibethicus, 1 KERR'S Linnaus, 1792. 

 Fiber zibethicus, CUVIER, R. A. I, 1817, 192. 



DESMAREST, Mamm. II, 1822, 279. 

 HARLAN, F. Am. 1825, 132. 

 GRIFF. Cuv. V, 1827, 208. 

 RICHARDSON, F. B. A. I, 1829, 115. 



DEKAT, N. Y. Zool. I, 1842, 75; pi. xx, fig. 2 ; pi. xxxii, fig. 3. (Skull.) 

 AUD. & BACH. N. Am. Quad. I, 1849, 108 ; pi. xiii. 

 KENNICOTT, Agric. Rep. U. S. Pat. Off. for 1856, (1857) ; plate xiv. 

 Lemmus zibethicus, FISCHER, Synopsis, 1829, 289. 



Ondatra zibelhicus, WATERHOUSE, Charlesw. Mag. N. H. Ill, 1839, 594, (fig. of skull.) 

 Musk beaver, PENNANT, Hist. Quad. 1781, No. 252. IB. Arctic Zool. I, 1784, 106. (Leverian Museum.) 



Body thick and clumsy ; in shape resembling the arvicolas. Neck indistinguishable. Feet 

 moderately large. Tail about equal to the body without the head. 



Head broad, depressed, acute. Eye very small ; its long diameter not equal to the width of the 

 two upper incisors ; its centre about midway between the tip of the nose and the posterior mar 

 gin of the ear. The ear is quite small ; nearly as broad as high : truncate and rounded above ; 

 there is no distinct tragus, the cartilage being entirely straight in this region. The antitragus 

 is, however, quite prominent, as a rectangular projection at the bottom, of the external ear; there 

 does not appear to be any natural arrangement in the ear to exclude water, but the dense fur 

 with which both sides are coated, and completely concealing it, answers the same purpose. 

 The external surface of the outer ear, however, is only hairy near the upper margin posteriorly, 

 leaving the rest of this surface to the anterior edge of the ear, and around and above the meatus, 

 entirely naked. The septum of the nostrils is thick, as wide as the upper incisors, and is 

 marked longitudinally by a broad shallow groove. There is a small papilla on the posterior 

 edge of the nostril which may serve as a valve to close it under water. The upper lip is not 

 split, but is hairy between the incisors and the nose. The lips are thick and fleshy, the upper 

 covered with hair a little within the margin. On each side of the upper lip there is an internal 

 projecting flap, which, when the two are brought together, completely overlap and conceal the 

 anterior portion of the palate, and reducing the opening of the mouth to a square aperture. 

 There are somewhat similar flaps on the lower lip folding over the base of the incisors. On 

 the inside of the upper lip, again, and placed behind the flaps above mentioned, is a square 

 patch of stiff hairs pointing backwards and inwards, and when the flaps are brought together, as 

 above described, are in contact with each other, and serve to diminish the size of the free open 

 ing of the inner mouth ; these patches are completely isolated from all the other hairs. There 



'The genus was established for 3fyopolamus coypus should not Kerr's name take precedence for this? 



71 L 



