288 "University of California Publications in Geology [Vol. 10 



Fronto-parietals flat, not fused in midline, scarcely concave; 

 dorsal surfaces considerably roughened ; sides nearly parallel and 

 projecting downward slightly around the cranium. Sphenethmoid 

 relatively large, deeply notched posteriorly, nearly in contact with 

 prootics behind and involving cranium in a more complete ossifi- 

 cation than in Recent toads of related species. Short posterior arm 

 of parasphenoid, pointed ; anterior arm below cranium wider than in 

 recent Bufo boreas; lateral wings below exoccipitals relatively and 

 absolutely wider than in other species of the group ; a strong trans- 



3 



Figs. 1-3. Bufo nestor, n. sp. Skull, No. 22468, X 2. Fig. 1, dorsal view; 

 fig. 2, ventral view; fig. 3, posterior view. Kancho La Brea Beds, California. 



verse ridge running medially through the lateral wings ; a roughened 

 triangular elevation below intersection of wings and shaft ; outer an- 

 terior borders of lateral wing not upturned in contact with pedicel 

 of pterygoid. Prootics extensively ossified, longer in proportion to 

 width than in Recent western toads. Squamosals small, triangular, 

 flat and roughened above ; lying in the plane of the fronto-parietals 

 and extending out above the prootics about half the length of the 

 latter. Foramen magnum slightly wider than high; condyles meeting 

 below ; extending about half way up sides of foramen and overlapping 

 edges of latter inside about 0.4 millimeter. ' ' Condyloid ' ' foramen 

 relatively and absolutely greater in diameter than in skulls at hand of 

 Bufo boreas boreas and B. b. halophilus. 



