Cape. J 562 [ Jan . 18> 



bone. The latter is about as long on its superior sutures as it is deep at 

 the orbit. It presents a distinct preorbital angle above a prominent tuber- 

 cle. The occipitoparietal suture extends well forwards, 30 mm. in advance 

 of the crest. The squamosal does not reach to the lateral occipital crest. 



The infraorbital foramen occupies the position it has in the A. ryderanus. 

 In a young specimen of A. guyotianus it has the same position as in 

 the adult. The frontal foramina are about as far apart as each is from the 

 supraorbital border. There is a postparietal foramen on the parieto squa- 

 mosal suture, and there are three postsquamosals, two of them near 

 together, and near the posterior suture, the other below the postparietal 

 foramen. Foramen ovale oval, about as large as the F. rotunclum, and 

 separated from the foramen lacerum by the produced base of the inferior ala 

 of the sphenoid bone. Palatine foramen opposite the third deciduous pre- 

 molar. 



Superior canine teeth robust, bases of crown one-half lenticular, the pos- 

 terior face truncate. A considerable diastema anterior to first premolar, and 

 a short one behind it. Other teeth in continuous series. First and second 

 premolars two-rooted ; absolutely simple. Third and fourth crown of first 

 of usual form. First true molar smaller than second. Enamel minutely 

 roughened. 



Measurements. M. * 



Length from supraoccipital crest to canine inclusive. . . .180. 



" " front of bulla 036 



" " " " " penultimate molar. .108 



" orbit (axial) 105 



" " front of orbit 126 



" of sagittal crest 048 



" " superior molars (last included) 076 



'' " premolars .036 



Diameters M. i \ anteroposterior 063 



. c transverse 014 



Diameters M. ii \ anteroposterior 0165 



t transverse .-. 020 



Width of skull at postglenoid inclusive 077 



" " '* middle of zygomas 050 



" " " fundus of canine alveolus 038 



" between canines 020 



" " second true molars 033 



" of skull at postfrontal processes 076 



" '' " between anterior rims of orbits «.066 



The label from this specimen is lost. It is, however, from Oregon, and 

 to judge from the color, from the true John Day epoch, rather than the 

 North Fork bed. 



