MURIDA—ARVICOLINA—ARVICOLA RIPARIUS. 
177 
TaBLe XLVI.—Measurements of sixty-eight skulls of eastern and western specimens of ARVICOLA RIPARIUS. 
Under jaw from 
Widthat—| 2 | & Z| & 
tas sd 4 B tip of incisors to— 2 2 
a A= | i |) 8 a A 
S| se | oe peels |S 
Locality. a S SI g |28 EI = Remarks. 
; “be She) | eee eel Sale 
3 ret SGT eval lmc=aiaees lee hace eee f= 
B ea Se Sa a ee ey ee ee ee EP 
S cS) 2 B = © o a = = ° Co) 
A R 5 N °o =) R 4 Aa ld = = 
O88) |p 0. 72 0. 30 
0.20 | 0.56 | 0.74 0. 33 
0.18 | 0.59 | 0.75 0. 34 
0.17 | 0.58 | 0.77 | 0.32 
0.20 | 0.61 | 0.77 | 0.30 
aotaa| fossa coast , . 25 | 0.30 | 
0.20 | 0.62 | 0.78 | 0.80 | 0.26 | 0.32 
WEP DT ps ar 0. 80 0.30) 0.35 
0.55 | 0.70 0.25 | 0.28 
aime) OSEO) | Pee ee Ose) | Ondo: 
0. 62'| 0.80} ---.. 0.27 0,35 
0.60 | 0.78 | 0.82 | 0.28 | 0.30 
S20) | Seterarel | tesa ala | meme 0.26 | 0.27 
0. O20) eater 0.74 | 0.76 | 0.24 | 0.30 
0. 0. 23 
+ 0. 0. 36 
$23 0. 0. 25 
20,00 Hingham, Mass... ...-- 0. 0.35 
+443, | Wood's Hole, Mass.--..- 0. 0. 32 
0. 0. 36 
0. 0.34 
0. 0. 30 
1 0. 0.31 
Ke z 0. 0.37 
FOgh Nichols; WN, Wie: 5 sac 0. 0. 36 
Jase Essex County, N.Y ..-. 0. 30 
1iif | Philadelphia, Pa... .... 0. 34 
945. | Foxburgh, Pa......-.-.. 0. 30 
one |... Gi icine Oreos 0. 33 
1977 3 ROLY gues Meee eel pace Premect iaeee 
9p2 1.08 | 0.44 | 0.62 17 | 0.27 | 0.20 0. 36 
2pB 1.05 | 0.43 | 0.63 16 | 0.25 | 0.24 0.34 
3323 AOS? 0-40) eee =e 0.15 | 0.27 | 0.18 0. 33 
Tigo 1.06 | 0.42 | 0.64 18 | 0.27 | 0.21 0. 32 
Aaze Heyy |e 0259) |) 07 15y}5 2-5. 0. 18 0. 30 
17.07 1.02 | 0.40 | 0.60 14 | 0.25 | 0.21 0, 32 
240 |...---0 -.---------2-----| 2222 |.-22--|eeee ee] =e 0.26 | 0.19 0. 30 
4860 1.00 | 0.40 | 0.53 | 0.17 | 0.24 | 0.20 0. 26 
Aber 1 07 | 0.40 | 0.62 | 0.15 | 0.27 | 0.22 0.31 
RANT Washington, D. C. 1.13 | 0.45 | 0.66 | 0.18 | 0.26 | 0.23 0. 36 
£970 Clarke County, Va 1.00 | 0.39 | 0.58 | 0.16 | 0.27 | 0.21 0.3L 
UIE West Northfield, Il ....| 1.05 | 0.42 | 0.58 | 0.15 | 0.27 | 0,22 0.31 
132.0 1.06 | 0.49 | 0.60 | 0.17 | 0.28 | 0.22 0. 32 
45455 1.10 | 0.40 | 0.62 | 0.1) | 0.28 | 0, 21 0.31 
fans 1.06 ;) 0.42 | 0.61 | 0.15 | 0.27 | 0.21 0.31 
12158 1.00 | 0.36 | 0.56 | 0.14 | 0.25 | 0, 22 0. es 
doing 0.96 | 0.38 | 0.64 | 0.14 | 0.24 | 0.20 0. 3 l 
pees 0.95 | 0.35 | 0.52 | 0.13 | 0.24 | 0.18 0.25 | Not full grown. 
424 Gb seso)seecss [oreeee USP til Beso ene Bee cieal ei) (sco 2 =i ze 
Ah 0.40 | 0.62 | 0.16 | 0.26 | 0.21 | 0.59 | 0.77 | 0.20 | 0.28 | 0.33 
pane Detroit River, Mich. .... 1.00 | 0.38 |..-... | 0.16 | 0.25 | 0.17 | 0.56 | 0.72 | 0.77 | 0.27 | 0.32 
12 M 
