MURIDAE—SIGMODONTES— HESPEROMYS LEUCOPUS. 



67 



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All the foregoing thirty-one specimens, from substantially the same local- 

 ity, were labeled "myoides" at the Smithsonian, and the cheek-pouches 

 appear to have been carefully examined by the naturalists who collected the 

 series. The pouches measure from a little less than two-thirds to a little over 

 three-fourths of an inch in depth from the nose, and about half as much in 

 depth from the angle of the mouth. Now these specimens, with an average 

 length of 3.64, have an average tail of 2.70 ; and in not one does the tail even 

 equal the head and body. 



The credit of first showing that H. leucopus has cheek-pouches is due to 

 Mr. Allen, whose suggestion that probably all the species of the genus would 

 be found to possess them we have verified in the cases of all the intimate 

 allies of H. leucopus examined. Professor Baird, however, had already sus- 

 pected their existence in this and other species. (Baird, op. cit. 472 ; Allen, 

 op. cit. 229.) 



Mr. Allen is therefore perfectly right in saying that H. "myoides" is 

 "positively identical with H. leucopus.' 1 It is hardly necessary to add that 

 this determination invalidates the analysis of the genus given by Baird, 

 op. cit. 458. 



The Hesperomys "gracilis" of LeConte is another nominal species. It 

 was referred by Baird to his "myoides" with a query. We have LeConte's 

 type before us ; it is tabulated in the foregoing table along with another speci- 

 men (No. 4710), also labeled "gracilis"; both are from Ohio, Wisconsin, or 

 Michigan, and are in the gray pelage. The larger one has the tail 3.60 long, 

 just about equal to the body, which latter, however, is stretched, and now is 

 rat-eaten. There is absolutely nothing to distinguish either of these speci- 

 mens from ordinary leucopus. H. "gracilis, LeConte" is a taxidetmal acci- 

 dent, the specimens having been stuffed so as to look slenderer than usual. 



We have before us the type and only known specimen of Hesperomys 

 "campestris," LeC, from New Jersey (No. 4726 of the preceding table). 

 LeConte's description shows nothing whatever different from ordinary leuco- 

 pus, and the specimen bears out the description. The animal is ungrown, 

 and from long immersion in alcohol (out of which it has been lately skinned, 

 in a wretched state of preservation) has lost every trace of its original 

 coloration. 



Of two specimens before us from Labrador, one (No. 3924) is labeled 

 "arcticus, Sauss.", and the other (No. 3925) "bairdii, Sauss." We trust that 



