PLEISTOCENE VERTEBRATES FROM CUMBERLAND CAVE 



61 



directed nearly at right angles to the line of the tooth row. [They are 

 directed more obliquely forward in Hodomys.] Anteroexternal valley 

 of Ml and M2 very shallow and absent in M3, [In Hodomys M3 has a 

 shallow but well-defined anterior reentrant in young specimens.] M3 

 with a well-defined posterointernal reentrant valley. [This fold is 

 absent in Hodomys.] 



As seen in mandibles U.S.N.M. nos. 12037 (fig. 34) and 12041, the 

 following additional characters appear as of generic importance: 



Figure 33.—Parahodomys spelaeus Qidley and Qazin: Right ramus of mandible, type specimen (U.S.N.M, 

 no. 12040), lateral and occlusal views. X 2. Cumberland Cave Pleistocene, Maryland. 



Symphysis relatively deep. Lower branch of masseteric ridge very 

 prominent and sharply defined. Condyle relatively large and de- 

 pressed so that condylar bar is directed backward to a much greater 

 extent than in Hodomys and the notch between it and the coronoid 

 process is much more widely open. 



Specific characters. — Size about that of Hodomys alleni. Incisors 

 relatively robust, causing a more prominent swelling of the lower 



Figure Z^.—PaTahodomys spelaeus Gidley and Gazin: Right ramus of mandible (U.S.N.M. no. 12037), 

 lateral and occlusal views. X 2. Cumberland Cave Pleistocene, Maryland. 



border of the ramus than in H. alleni. Diastema between incisor and 

 cheek teeth long. Posteroexternal reentrant folds in all molars 

 shallow and pocketed at base, wearing at occlusal surface in wide 

 open U-shaped pattern from summit to base of crown. Postero- 

 internal reentrant fold well developed in M3, extending somewhat 

 below middle of crown but disappearing in old age. 



The material referred to this form includes seven lower jaws in 

 addition to the type, representing individuals in several stages of 

 maturity. 



Comparison. — The genus here described is known only from lower 

 jaws but fortunately these reveal diagnostic characters that clearly 

 distinguish it from the nearest related living genera, Neotoma and 



