98 



MEMOIRS OF THE CARNEGIE MUSEUM 



blade by a rather deep groove. The latter element is low, sharp and oblique in 

 position. 



Molars ^-^ are proportionately broad transversely and short antero-posteriorly. 

 Each of these teeth supports two subequal external cones separated by a rather deep 

 depression from a single crescentic internal cusp at the base of Avhich is a broadly 

 expanded basal cingulum. Strong basal cingula are also developed on the external 

 sides of M. ^-^, more especially M.-, and on the antero-external angle this is devel- 

 oped into a considerable prominence. M.^ is wanting on both sides of our speci- 

 men, but on the left it is represented by two alveoli, as shown in Fig. 7. These 

 show it to have been rather large for a third molar and to have been aligned with 

 the external margins of molars ^-^ . 



Fig. 7. Crowu view of superior dentition of type of P roamphicyon nebrascensis Hatcher (So. 491). Natural size. 



Measurements of Type (No. 491). 



Length along palate and base of cranium from incisive alvelolar border to 



opening of foramen magnum 175 mm. 



Greatest height of sagittal crest 25 " 



Length of sagittal crest, estimated , 92 " 



Distance along median line from union of superciliary ridges to anterior ex- 

 tremity of nasals 86 " 



Distance from posterior border of M.^ to anterior border of I.^ 85 " 



Antero-posterior diameter of canine at base 9.5 



Transverse " " " " 6.5 " 



Length of premolar series 37 



" sectoral 12.5 



" molar series 26 



Antero-posterior diameter of M.- 11 



Transverse diameter of M.i 16 " 



Relations of Proamphtcyon Nebrascensis. 



After a careful comparison of the type of the present genus and species with 

 Wortman's description and figures of Amphicyon americanus already referred to, 

 the writer believes that the skull which forms the type of the present genus and 

 species pertained to an animal intermediate in character between Daphoenus and 

 Amphicyon and which stood in the lin? directly ancestral to the latter genus. The 



