SCIUUID^— CYN0MY8, 



891 



In Cijnomys, the edges of the orbits arc raised obovo the piano of the 

 frontals, as in several of the spccties of the subgenus Colohofi.i, but rather 

 more strongly, and the anterior face of the zygomatic process of the maxiihiry 

 is deeply excavated. The breadth of the skull at the posterior border of the 

 zygomatic arches is equal to or greater than the length of the skull, exclusive 

 of the portion anterior to the front edge of the maxillaries, and hence much 

 greater than in any other genus of the Sciuridte. All the teeth are relatively 

 large and heavy; the grinding teeth arc narrowed on the inner border, as in 

 Spennophilus and Arctomys. The molar series occupy about one-third the 

 entire length of the skull. The incisors are short and strong, with the antero- 

 posterior breadth nearly twice the transverse.* 



The genus Cynomys was proposed by Kafinesque in 1817, and based 

 wholly on the description of the "Barking Squirrel" of Lewis and Clarke, 

 which he named Cynomys socialis. He also doubtfully referred to it a 

 "Cynomys grisea", based on the "Petit Chien" of the Upper Missouri, inci- 

 dentally mentioned by Lewis and Clarke. This is merely another name for 

 the Barking Squirrel of the same i\wt\wrs {^= Arctomys ludovicianus Ori\,=: 

 Cynomys ludovicianus Baird). In. the same article (and on the same page), 

 Rafinesque also proposed the genus Anisonyx, based primarily on the descrip- 

 tion of the "Burrowing Squirrel" of Lewis and Clarke {=: Arctomys colutii- 

 hianus Ord,:=: Cynomys gunnisoni Baird), but which was made to include also 

 their "Sewellel" under the name Anisonyx rufa, wliich belongs to a wholly 

 different family (HaplodontirleB). The genus is based on wholly false charac- 

 ters, resulting from Rafinesque's misinterpreting Lewis and Clarke's descrip- 

 tion, and, as far as the present group is concerned, is preoccupied by Cynomys. 

 The first species referred to it is the Anisonyx brachiura, equal to the Arctomys 

 columbianus of Ord of two years' earlier date, based on the same description. 



The genus Cynomys is restricted to the parks and plains of the jrea?^ 

 Rocky Mountain Plateau, and is represented, so far as known, by only two 

 species. 



* The food of Cymmya consisting of soft berbRceons [ilants and grosses and succulent roots, tbe large 

 size of tbe teeth and their very flrm implantation offer a puzzling problem. The great antero-posterior 

 brea<ltb of the ineisorR, tbe buav- , strong molars, and all tbe provisions of the skull forniuscnliirnttnch- 

 meut indicate great strength of jaw and cutting power— far greater even than in the true Scpiirrels, 

 whose food couHists largdy of hard nuts. The species of Cynomyt live on the open, barren plains, gen- 

 erally where the coarsest plants are annuals, with stalks rarel~ thicker that one's linger, and the only 

 suffruticuso vegetation is the various forms of Arttmiiiia, Oilone, etc. Where the eastern C. ludovicianm 

 must abounds, there is appai jtly nothing for it to feed upon requiring great strength of Jaw or heavy 

 dentition. Yet it presents the heaviest dentition and greatest masticatory power mot with among the 

 Siiurida:. 





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