A FOSSIL OWL FROM THE BRIDGER EOCENE. 

 BY ALEXANDER WETMORE. 



In 1873, Dr. Joseph Leidy described some fragments of bone, 

 supposed to be those of a large lizard from the Bridger deposits of 

 Wyoming as Saniwa major, basing this name on the distal end of a 

 humerus and two fragmentary vertebrae. The type specimens 

 preserved -in the collections of the Academy of Natural Sciences of 

 Philadelphia were borrowed recently by Mr. C. W. Gilmore, who 

 had recognized that the type material was probably composite, and 

 to him and to Dr. Witmer Stone, I am indebted for permission to 

 study the humerus in question, which proves to be that of a bird. 



Though Dr. Leidy considered this humerus as lacertilian, and 

 compared it with that of a monitor, it is readily seen that it does 

 not belong in this group as there is no sign of an epiphysis on the 

 articular end of the bone. The specimen is well fossilized, and is 

 dark green in color save along the condyles, where it is lighter and 

 has a somewhat chalky appearance, a circumstance that perhaps 

 led to its allocation in the Sauria, as it may have been thought that 

 this lighter area was epiphysial in character. 



The two broken vertebrae mentioned must stand as the type of 

 Saniwa major Leidy and are hereby so designated. The avian hum- 

 erus, representing an owl of the family Bubonidae, may be known as 



Minerva saurodosis sp. nov. 



Characters. — Distal end of humerus (figs. 1 and 2) similar in 

 general form to Bubo virginianus (Gmelin) but smaller, with radial 

 and ulnar trochleae reduced in size; ulnar trochleae less produced 

 distally toward outer end; angle at base of ulnar condyle on inner 

 anterior face sloping gently (not abrupt) ; surface above entepicondy- 

 lar process broader, less elevated, sloping gradually into brachial 

 depression; entepicondylar process slighter, lateral margin of bone 

 above ectepicondylar process relatively less broadened, with more 

 rounded margins, expanding to support entepicondyle; shaft ex- 

 panding somewhat to support ectepicondylar process. 



Description. — Type, Acad. Nat. Sci. Philadelphia, no. 9131, 

 distal end of left humerus, from near "Lodge-Pole Trail Crossing 

 Dry Creek," about ten miles from Fort Bridger, Wyoming; Eocene 



(455) 



