MURIDJ5— ARVICOLIN^E— AEVICOLA 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 

 hend 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 i to i 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 ru. 

 The coronoid process is very slender, falcate, and acute ; it rises fairly above 

 the level of the top of the condyle ; its apex is generally just about I an inch 

 from the tips of the incisors, and when the jaw is in situ is just visible over 

 the upper edge of the zygoma. The greatest depth of the whole skull (closed 

 jaw included) is opposite the anterior part of the orbits, and amounts to 

 nearly f 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. 



Table LVI. — Measurements of fourteen skulls of Ahvicola (Pitymys) pinetorum. 



