Some Notes on the Mammals of Mammoth Cave, Ky. 



57 



zygomatic breadth; length of nasals nearly half the basilar 

 length; greatest depth (occipital) about half the length of 

 mandible. Posterior margin of palate acutely emarginate, 

 nearly reaching a line connecting the hinder bases of m. 3. 

 Pterygoid fossa narrow and deep, the pterygoid processes 

 much constricted and strongly produced posteriorly below the 

 level of the audital bullae. Nasals scarcely reaching back to 

 a line connecting the anterior angles of the orbits, and falling 

 short of the premaxillaries in this respect. In yearling adults 

 the molars are sharply angled; m. 1 having two small anterior 

 and one large transverse median triangles and a posterior 

 lateral loop ; m. 2 is similar with only a single anterior triangle ; 

 m. 3 has an anterior triangle and a deeply indented, almost 

 circular, posterior loop. In very old examples these teeth 

 change materially, becoming broader and much less angular, 

 the tips of adjoining triangles and crescent sometimes joining 

 in a continuous outer enamel wall, and the anterior triangle 

 of m. 1 resolving into an indented crescentine loop. 



Measurements of male specimen, taken before immersion in 

 spirits : 



Millimeters. 



Total length 429 



Tail vertebrae 190 



Hind foot 42 



Height of ear from crown. . 24 

 Greatest breadth of ear.... 22.5 

 Skull, total length 55 



Mill 



meters. 





. 48 



Greatest breadth 



• 27.5 



Interorbital constriction.. 



• 7-2 



Length of nasals 



22 



Length of mandible 



• 32-5 



Width of mandible 



. 16 



General remarks. The above measurements are of an old, 

 adult, male rat, and are about the average of fully-grown speci- 

 mens of this species. The only difference which seems to be 

 constant to cave-dwelling specimens, as compared with those 

 from more open cliffs and rocky ledges, is the less hairy and 

 markedly unicolored tail. I find that two specimens in the 

 Academy's collection from a cave in Wythe County, Virginia, 

 correspond, in this particular, with those from Mammoth 

 Cave. In all other respects, there are no constant peculiari- 

 ties in the Kentucky animal which are not shared by Pennsyl- 

 vania specimens. 



For the benefit of those who are unable to look up the liter- 

 ature to which references have been made, it may be stated 



