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116 



MONOGRAPHS OF NORTH AMERICAN RODENTIA. 



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This remarkable rat lias hitherto only been reported from the Southern 

 Atlantic seaboarfl, whore it is said to be abundant, particularly in the rice dis-, 

 tricts. It is eminently aquatic ; in this respect equaling the Arvicola amphi- 

 bius of Europe, and, in our country, only surpassed i)y the muskrat. Its whole 

 structure, but particularly its feet and ears, point to its amphibious nature. 

 Several specimens in the present collection, from unsuspected localities, enable 

 us to greatly extend its known range. Several were taken in Kansas liy Mr. 

 ]J. F. Goss, who also forwarded from the same locality in that State (^Neosho 

 Fails) examples of Onychomys leurognster, Pedomys austerus, Synaptomys 

 cooperi, and otiier interesting animals. These Kansas specimens of Oryzo- 

 mys are larger than Carolina or Georgia ones, and otherwise a little differ- 

 ent in having heavier tails, lighter colors, &c. ; but do not raise a suspicion 

 of specitic'distinction* 



The original Mus jmlustris of Harlan purports to be from New Jersey ; 

 and, as there is no reasonable doubt of this, it is the northernmost recorded 

 locality. Tiiere is little to be said of the bibliography of the species ; in 

 fact, the "General Remarks" in Audubon and Bachman, which are here repro- 

 duced to settle the question of Mus palustris, Harlan, comprise everything 

 essential. "We obtained," they say {op. cit. 216), "specimens of Arvicola 

 oryzioora in tlie winter of 1816, but did not describe it until May 1836. . . . 

 Having occasion to send descriptions of several, then undescribed, species to 

 the Academy of Natural Sciences of Piiiladelphia, we sent a specimen of 

 this animal to Dr. Pickering, requesting him and Dr. Harlan to compare it 

 with the Arvicola riparius of Okd. ... In searching in the Academy, a speci- 

 men of this species was found, and Dr. Harlan, in opposition to the views 

 of Pickering, felt himself authorized to publish it in Silliman's American 



* A Bpecimen, No. 94:il>, from Tiicliitnn, Tehuantcprc (Professor Stimichrcut), I caDiiot distin(;uiHb 

 from the ordinary palmlrit of Cnrolina. It la about 4.25 long ; tail, 4.50 ; foot, l.iiO. In color, it is a 

 little clearer tlian most Carolina Bkins, yet not of the paler yellowiBh-brown noticed in Kansas ones, but 

 rntber a brigbler fnlvons-bronn ; the under parts are nnnsnally pure wbito. I have not met wii^h any 

 Mexican quotations of Orj/zomys ; but if any species has been described from Mexico, and of which No. 

 !)4'36 is an example, it cannot well prove difl'ereut from patutlris. The cose seems to me to be parallel 

 with that of the 8igmo<1ona elsewhere discussed. 



Two Jamaican skins of Orysomyii (Nus. 7775 and PUT), received since the preceding was written, 

 agree completely with paluilris in size and shape, bnt are noticeably difierent in color. They are of a 

 rich furrugineous-brown, oiily'a little darker along the back, and the under parts are strongly washed 

 with a dilution of the same. The difference, indeed, from the ordinary dark Carolina palutMi, is nearly 

 as evident as iu some of tlio dullest Ilmperomyt OHreoluB compared with hucopm. Probably these siwci- 

 mens represent a race if not a good species ; but, in my ignorance of the pbysico-geograpbical iofluencea 

 that work npoa the West Indian rats, I cannot pursue the subject, and especially refi'ain from giving any 

 name to the animal, aa I presume it baa been described, thongh 1 have not met with any reference to it. 



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