MURID^E— ARVICOLINiB— ARVTCOLA EI PARTUS. 



173 



Table XLIV. — Measurements of thirty-nine dry specimens of the RIPARIL'S type from various localities in the 

 United States west of the Mississippi — Continued. 



As will be seen, this series embraces the type-specimens of all the 

 nominal species we are to discuss except "montana", and of this there is 

 a typical example. The series was made up without the slightest reference 

 to any desired or expected result, and simply includes, in fact, all \ he dry speci- 

 mens that have come under our observation. The seven specimens marked 

 "young" are not grown enough to furnish available measurements; and as 

 they would vitiate the result if included, they are omitted in computing the 



It is hardly necessary to more than allude to the average of this series 

 as compared with the eastern ones. The total length falls between that of 

 the Philadelphia and the Illinois series, and is 0.15 below the general average. 

 The length of tail is within a just appreciable fraction of the grand eastern 

 average, taking place between that of the general series and the Illinois 

 series. The average proportion of body and tail is (4.18 : 1.53) as 1.00 to 

 0.34, precisely as in the Philadelphia and Massachusetts series. The average 

 foot is precisely as in the Illinois series, and within 0.01 of the grand eastern 

 average; only two feet touch 0.90, and none (of the adults) fall below 0.70. 



