a 







11- .- 



iir 



176 



MONOGRAPHS OF NOIITIT ^ MERICAN RODE^TIA. 



Tablr \LV.—Me<uuremeHU nf thirteen alcoliohe. $peclmeHM of A. riparius y)v)«i (Ac V»ttti State* tcett nf the 



UiiuiMlppi. 



* Dtexler's numerous Fort Itriilger Hpecimens wo have not tboni^ht necessary li> measnra in detail, as tlmy differ but 

 Utile, and are proclaely like the dry ones alrt'ndy preseot^d. McCnrttiy'o, from the snnio locnlity . show h good deal of iitficrciic* 

 in length nnd stutitnoiu of tail. It will bo observed thrtt these Hpectmena, which we cannot diatiu^^tflh even as a Inonl strain, 

 fmni ordiuary ripariui, were collooteil la company with a lot of A. autte.tu var. decurtatu*, wliicli aoeina oomnton in thai 

 locality, and is distingtiiiihable al a glnooe. Kvon the collectors appear to have separated the two species, tojudgo from tbo 

 labels. 



t Uy some miHprint in Boird's work, Not. 130!>, 13T0 are given as mounted, whereas they now lie before us In nloohoL 



Having exhausted our data of size and external shape, we will next inter- 

 rogate an extensive scries of skulls of eastern and western Arvicolas of the 

 riparhts section, to see if there be any cranial characters upon which more 

 than ii single species may be predieable. ' 



H '^ \ 



