MUIIIDAE— 8IOMODONTES— HESPEROMYS LEDCOPU8. 



61 



between these extremes is hence about fifty per cent, of the me^n — n striking 



example of the unreliability of this character as a specific distinction 



The number of the vertebnc varies from twenty-four or twenty-five to above 

 tiiirty. In regard to absolute size, the length of the head and body together 

 in Massachusetts specimens rarely exceeds four inches; the average is between 

 tliree and a quarter and three and a half; perhaps nearer tho 'i.tter." 



In continuation of this matter, we next bring in our entire series of 

 Hesperomys Icucnpus from Eastern North America, embracing specimens from 

 Labrador to the Carolinas, and westward to Kansas, inclusive (our Arctic 

 and western examples are elsewhere tabulated and discussed). We admit to 

 this series only what we claim as unquestionable leucopus jiropcr, excluding 

 even the recognizable geographical races. And even after this exclusion, 

 there are six nominal species from the region just indicated requiring our 

 attention. 



Taule Xl.--i£e(uuremenl» ojabout one hiindral (and lint of many more) tpccimcfit of Hksfkromys lkucopus 



from Eastern Sorlh America. 



[N. B. — All iDOflHnrtMl dry UDless olberwtiso atAt«<1.] 



