MURIDA—ARVICOLINH—ARVICOLA PINETORUM. 221 
under jaw there is a very nice characteristic of pinetorum as compared with 
any other species we have examined. Owing to the shortness and upward 
bend of the descending process, or else to some difference in the curve of the 
whole jaw, the distance from the tips of the incisors to the tip of this process 
is no greater than the distance from the same point to the back of the con- 
dyle; whereas, in the other species, the former measurement is appreciably 
longer than the latter. The upper molar series measures from 4 to + of an 
inch in length; the under a trifle more, usually. The upper incisors project 
+ of an inch, or a little less, from the alveoli; the under ones from + to 35. 
The coronoid process is very slender, faleate, and acute; it rises fairly above 
the level of the top of the condyle; its apex is generally just about } an inch 
from the tips of the incisors, and when the jaw is i situ is just visible over 
the upper edge of the zygoma. The greatest depth of the whole skull (closed 
jaw incladed) is opposite the anterior part of the orbits, and amounts to 
nearly $ of an inch. The interparietal is (usually) subtruncate laterally; the 
bony palate has precisely the formation of Arvicola proper; the nasal branch 
of the intermaxillary extends a little beyond the end of the nasals, as in 
Pedomys ; and we notice nothing peculiar in the individual cranial bones or 
their sutures or foramina. 
Taste LVI.—Measurements of fourteen skulls of ARVICOLA (PITYMYS) PINETORUM. 
Width at—| 2 : Jaw :—tip of inci- 2 6 
S 2 sors to— a 
a i} B ° 
Lom n = D 
aS er ep te om 
No. Locality. G 5 | 2 a 3s 3 | 2g g 3 a 
ie dig tana |) ate eet erase eres eee Na 
ee ep ° =) 2 2 5 Ss Soa < 
=] = &o 2 = =) af =) | 2 a |c ‘) 
oO & b u = a S o oS | a =] 
BOP y aI CO) Oates aeeeerl ae ae 0.36 | 0.50 | 0:18 | 0.20 | 0.16 | 0.50 | 0.60 0.60 | 0,20 | 0.25 
$852 | Pennsylvania....-.-- 0.97 | 0.40 | 0.62 | 0.19 | 0.25 | 0.19 |..-... 0.75 | 0.74 | 0.24 | 0.27 
tii4 | Bladensburg, Md. -..-.|.-.--- OFS8"OS58) OMe 0.20 | 0.58 | 0.75 | 0.75 | 0.26 | 0.28 
#952 | Clarke County, Va...|..---.|.----.|------ 0.18 | 0.23 | 0.18 | 0.47 | 0.65 | 0.65 | 0.22 | 0.25 
2073 |... Gor seeess eens 0.92 | 0.35 | 0.55 | 0.18 | 0.22 | 0.17 | 0.51 | 0.67 | 0.67 | 0.23 | 0.27 
2968 | oo... ria ee ae Na Re Le ed en eee 0.24 | 0.19 | 0.55 | 0.70 | 0.70 | 0.25 | 0.28 
1222 | Tarborough, N.C. .--- 0.93 | 0.37 | 0.58 | 0.08 | 0.25 | 0.20 | 0.58 | 0.72 0.72 | 0.25 | 0.29 
ae Gots cee ess 0.95 | 0.37 | 0.60 | 0.18 | 0.25 | 0.22 | 0.56 | 0.72 | 0.72 | 0.28 | 0.30 
ES hg ee Gy tat yds fad ON eeceel=toal seo aeel Naseme aciece 0.19 | 0.23 | 0.17 | 0.50 | 0.65 | 0.65 | 0.24 | 0.26 
$224 | Society Hill, S.C. ..--|.----- 0.37 | 0.63 | 0.20 | 0.25 | 0.15 | 0.52 | 0.70 | 0.70 | 0.25 | 0.28 
Deva Georeid see <aasa OF90h| 50837. |Sa2-5- 0.18 | 0.25 | 0.17 | 0.50 | 0.66 | 0.66 | 0.27 | 0 25 
S000 |------ doeaaiaeee 0.91 | 0.34 | 0.53 | 0.17 | 0.23 | 0.12 | 0.51 | 0.63 | 0.63 | 0.22 | 0.20 
eae lees = « Gok nce hens oe 0.90 | 0.36 | 0.58 | 0.19 | 0.22 | 0.17 | 0.53 | 0.65 , 0.65 | 0.24 | 0.27 | 
3950 |. ..-. GOee teen aces OF90) Po =-. 0.54 | 0.17 | 0.23 | 0.18 | 0.50] 0.65 0.65 | 0.25 | 0,29 
