MUIUD^E— AEVICOLLN^E— ARV1COLA KIPARIUS. 



169 



exactly one and three-fifths inches; and a foot of 0.78, or nearly four-fifths of 

 an inch. The majority of the specimens run from 4.25 to 4.50 in length; a 

 large proportion run between 4.00 and 5.00. Only eight specimens (about 7 

 per cent, of the whole) exceed 5 00, and only twelve (about 10 per cent.) of 

 the adult ones fall below 4.00. The proportionally longest tail is as 0.41 to 

 1.00, or a trifle over two-fifths of the trunk; the shortest tail is as 0.27 to 1.00, 

 or a little over one-fourth of the trunk; the average tail is to the average trunk 

 as 0.37 to 1.00, or about three-eighths. Only a single foot of the 114 exceeds 

 0.90, and only three touch this figure; not one falls below 0.70. 



The limits of what may be called normal individual variability are easily 

 set from the foregoing figures, and the bounds of possible variation as readily 

 perceived for both absolute size and relative proportion of parts. It must 

 be observed that we have not yet presumed to inquire whether more than 

 one species be represented in the series; but what we claim to have shown 

 is that no more than one species can be predicated upon these specimens 

 from size and relative proportion of parts, since the absolute dimensions grade 

 imperceptibly between the extremes, and the relative measurements are 

 inextricably interlaced. 



As a supplement to the foregoing, we subjoin another table of more 

 detailed measurements of numerous alcoholic specimens, all from the Eastern 

 United States. This table extends and checks the above results to the last 

 details of structure, and requires no further comment. 



Tablk XLIII. — Measurements of forty-five {and list of many other) alcoholic specimens of A. KIPAIUC8 from 



the Eastern United States. 



