PLEISTOCENE VERTEBRATES FROM CUIMBERLAND CAVE 67 



0. annedens seems to stand as a well-defined species of Ondatra but 

 is presumably less advanced than the living species. Neojiher may- 

 be considered as still less advanced in the development of the pattern 

 reached in Mi, although more advanced in degree of hypsodonty. 



Family ZAPODIDAE 



ZAPUS species 



The genus Zapus is represented in the Cumberland Cave material 

 by part of the right ramus of a mandible, U.S.N.M. no. 7777, carrying 

 all the cheek teeth. Tliis jaw represents an old individual in which 

 the teeth are considerably worn. They nevertheless present the 

 characters peculiar to the genus to which the specimen is referred and 

 show certain peculiarities that prevent assigning the form to any 

 Imown species. The material, however, is not sufficiently complete 

 to warrant establishing a new species. 



The tooth crowns of Mj and M2 are relatively shorter and the an- 

 terior main lobe of Mi is relatively wide as compared with those 

 examined of a large series of specimens of the living species. 



NAPAEOZAPUS cf. INSIGNIS (Miller) 



A second lower jaw, U.S.N.M. no. 12366, of a jumping mouse in the 

 collection is recognized as belonging to the woodland form Napaeo- 

 zapus. This jaw fragment is from the left side and has the incisor and 

 last two molars preserved. Mi is represented by the alveoli and root 

 portions. The jaw is distinctly larger and has larger teeth than the 

 specimen referred to Zapus. Moreover, the two molar teeth show a 

 tightly folded, complex pattern on the occlusal surface, which re- 

 sembles Napaeozapus more closely than Zapus. 



The fossil compares favorably in proportions with specimens of the 

 living species, N. insignis, differing in having a slightly more robust 

 incisor, which appears to be somewhat less curved than is common in 

 the modern form. Also, the alveoU for Mi suggest that this tooth may 

 have been a Httle longer anteroposteriorly than in A^. insignis. 



Family ERETHIZONTIDAE 



ERETHIZON cf. DORSATUM (Linnaeus) 



Figure 37 



The porcupine is represented in the Cumberland Cave collection by 

 about 15 determinable specimens, including the greater part of 3 

 skulls and 12 broken lower jaws. 



In North America, accordmg to Miller's fist of Recent mammals 

 (Miller, 1924), there are two living species of Erethizon now recog- 

 nized: E. dorsaium and E. epixanthum. The former comprises two 

 subspecies and the latter five subspecies. Apparently the distinction 

 between the two full species is based solely on color differences in the 



