SGIUEOMOEPHA. 831 



ridges, which are connected with each other and with the posterior external 

 V by a zigzag ridge. The anterior intermediate tubercle is an enlargement 

 of a crenate ridge which connects the internal edge with the external ante- 

 rior V. In the inferior series the molars have those lobes on the edge of 

 the inner side, of which the middle one is the least prominent. There are 

 two better defined lobes on the external margin. The crowns are basin- 

 shaped, and although the enamel is wrinkled in a complicated manner, the 

 wrinkles are not elevated, as in the other species of the genus. Thus the 

 inferior molars more nearly resemble those of ordinary Sciuridce than do those 

 of the other species of Meniscomys. The inferior incisor is much compressed. 

 The inferior border of the masseteric fossa is well marked and ter- 

 minates forwards below the middle of the second molar. The base of the 

 coronoid rises opposite the posterior pai*t of the third molar. A femur has a 

 cylindrical shaft. The distal portion is not elevated, and the rotular groove 

 is rather wide and with equal lateral ridges. The condyles are narrow 

 anteroposteriorly, and are spread well apart. A broken tibia is quite elon- 

 gate, and the distal part of the shaft is subcylindric. The proximal part is 

 triangular in section. The inner side above is a little concave, the posterior 

 side is a little more concave, while the external side is rather strongly con- 

 vex. The crest is not prominent. 



Measurements. 



u. 



Width of skull just behind postorbital angles 0066 



Length of otic bulla 0115 



Width between otic bullse 0038 



Length of superior molar series 0083 



Diameters second molar J ''°*«^<'P°«t«"«' 0028 



c transverse 0023 



Diameters last molar 5 '»°'«r°P°«t«"'''- 0023 



< transverse 0020 



Length of inferior molar series 0090 



Diameter third molar ^*''''"^^*'""«--. 0018 



< anteroposterior 0025 



Width of inferior incisor 0010 



Depth of ramus at front of Pm. iv 0040 



Depth of ramus at front ofM. iii 0060 



Width of condyles of femur 0060 



Depth of condyles of femur 0050 



Depth of fragment of tibia 0320 



Diameters head of tibia I '^°**"^''P°«*«^'°' "060 



< transverse 0060 



From the John Day River region, Oregon. 



