Vol. 6] Miller: Avifauna of Pleistocene Cave Deposits. 



393 



slightly smaller than the Recent specimen of G. melanoleucus at 

 hand which displays also a slight difference in the disposition of 

 the pneumatic foramina. The two specimens probably belonged 

 to birds of the same species. 



Additional material of the Recent species of long-shanked 

 eagles from South America may later make it possible to define 

 the cave form as to species. It does not seem wise at present, 

 however, to do so. 



BUBO VIRGINIANUS (Gmelin) 

 This owl is represented in a phase perfectly similar to the 

 existing form in so far as osteological characters and size are 

 concerned. A lower jaw, perfect except for the left angular and 

 articular region, corresponds in every particular with a specimen 

 of the western subspecies, B. v. pacific us. A humerus and two 

 femora, though fractured at the ends, display characters suffi- 

 cient to place them in this species. The species is represented 

 only in the Samwel Cave collections. 



BUBO SINCLAIR!, n. sp.s 

 Type specimen no. 7092, Univ. Calif. Col. Vert. Palae. Right 

 tarsometatarsus. Potter Creek Cave ; cotype no. 8952, a tibio- 

 tarsus from Samwel Cave. The species is characterized by its 

 very large size. The great gray owl, Scotiaptex nebulosa, is gen- 

 erally conceded to be the largest of the American owls, and 

 perhaps equals in size the largest known member of the group. 

 The cave form was compared with a large female specimen of 

 this species in the University of California Museum of Vertebrate 

 Zoology and was found to be quite appreciably larger. The 

 snowy owl, Nyctea, was also inferior in size to the fossil specimen. 



On comparing the tarsi of Bubo and Scotiaptex, there are several points 

 of difference which appear at once, though the size is almost exactly the 

 same. In Bubo the shaft is much more curved, the axis being concave 

 from without where that of Scotiaptex is almost perfectly straight. The 

 outer border of the external articular face is raised higher, the supra- 

 tendinal bridge is narrower, the gorge under it much broader, the papilla 



s This species is named in honor of Dr. Wm. J. Sinclair, who was actively 

 connected with the early exploration of the Shasta caves. 



