178 



MONOGRAPHS OF NORTH AMERICAN RODENTIA. 



TABLE XLVI. — Measurements of sixty-eight skulls of eastern and western specimens of Akvicola hipahius- 



Continned. 



w 



\m 



tm 



W 



mt 



Hit 



mi 

 an 



ityrfw 

 Hit 



Locality. 



Racine, Wis 



Saint Louis, Mo 



do 



do 



Prairie Mt-r Rouge, La. 



do 



Monterey, Cal 



do 



Petaluma, Cal 



San Diego, Cal 



Upper Pit River, Cal . . 



Lost River, Cal 



Fort Tejon, Cal 



California 



Dea Chutes, Oreg 



Puget Sound, Oreg 



1.03 

 1. 04 

 1.04 

 1.02 

 1.10 



1.00 

 1.18 

 1.13 

 1. 16 



1.08 

 1.01 

 1.05 

 1. 14 

 1.07 

 1.18 



0.40 

 0.42 

 0. 39 

 0.40 

 0. 45 



0.40 

 0.41 

 0.44 

 0. 12 



0.42 

 0.42 

 0.43 

 0.40 

 0.42 



Width at- 



N 



0.53 

 0.62 

 0.60 

 0.56 

 0.6? 

 0.60 

 0.62 

 0. 68 



0.60 

 0.64 

 0.61 

 0. 68 

 0.63 

 0.65 

 0.63 

 0.62 



0. 16 

 0.17 

 0.18 

 0.18 

 0.18 

 0. 16 

 0. 15 

 0.15 

 0. 10 

 0.14 

 0. 17 

 0.15 

 0. 15 

 0.14 

 0.19 

 0.15 

 0.18 



0.26 

 0.26 

 0.27 

 0.23 

 0.27 

 0.25 

 0.27 

 0.25 

 0.30 

 0.30 

 0.30 

 0.37 

 0.27 

 0.25 

 0.28 

 0.25 

 0.27 



Under jaw from 

 tip of incisors to— 



0.21 

 0.18 

 0.24 

 0.20 

 0. 22 

 0.20 

 0.22 

 0. 17 

 0. 18 

 0.23 

 0.20 

 0.22 

 0. 22 

 0.22 

 0.22 

 0.20 

 0.21 



0.60 

 0.61 

 0.60 

 0.58 

 0.64 



0.62 

 0.66 

 0.67 

 0.64 

 0.63 

 0.61 

 0.68 

 0.60 



« 



0.78 

 0.78 

 0.80 

 0.74 

 0.80 

 0.76 

 0.80 



0. to 

 0.81 

 0.80 

 0.82 

 0. 80 

 0.79 

 0.81 

 0.80 

 0.81 



(i 82 

 0. R0 

 0.85 

 0.77 

 0.83 

 0.79 

 0.81 



0.84 

 0.85 

 0.85 

 0.84 

 0.87 

 0.80 



0.84 

 0.83 



0.27 

 0.27 

 0.27 

 0.25 

 0.27 

 0.25 

 0.27 



0.29 

 0.30 

 29 

 0.29 

 0.23 

 0.21 

 0.27 

 0.25 

 0.30 



0.32 

 0.31 

 0.32 

 0.33 

 0.34 

 0.30 

 o. 33 



0.33 

 0.35 

 0.30 

 0.38 

 0. 37 

 0.36 

 0.32 

 0.32 

 0.35 



Remarks. 



utontumiH ' 



edax. 



mw.tanus 1 



tdax. 



lojlc/ rohtris. 



californiitis. 

 occidenta.ui. 



The blanks in (lie foregoing table are owing to the defective condition 

 of certain specimens. The measurement of the length is made from the tip 

 of the nasal bones to the upper border of the foramen magnum. The height 

 is the perpendicular from the posterior corner of the last upper molar. The 

 orbital width is at the point of greatest constriction of the orbit. The zygo- 

 matic width is at the broadest point of the zygomatic arches. The molar 

 series are measured from anterior corner of the first molar to posterior corner 

 of the last one. The length of incisors is their protrusion from the alveoli. 

 The condyloid dimension is measured to the back corner of the condyle. 



The average length of the whole series is 1.08; the minimum* is 1.00 

 and the maximum 1.20, the latter occurring in one of the "breweri" speci- 

 mens. The variation is, therefore, 0.20, or about 20 per cent, of the mean. 

 The average zygomatic width is 0.64; the maximum 0.69; the minimum 

 0.55. The proportion of length to width is, therefore, as 1.0* to 0.64, 

 or as 1.00:0.59. The molar series in both jaws is about the same, and 

 averages a little over 0.25 of an inch (from 0.24 to 0.30) ; the upper incisors 

 protrude about 0.20 on an average (from 0.17 to 0.24) ; the under are rather 



table. 



"Of adult specimens : several young skulls, ranging from 0.80 to 1.00, are excluded from the 



