2 Re ee 
0. C. Marsh on Cretaceous and Tertiary Birds. 213 
ulnar and radial condyles, and the remarkably ba oval, im- 
i ial muscle 
show unmistakably that this humerus belongs to one of the 
Shearwaters, and apparently should be placed in the genus 
‘e 
American paleontology. 
Catarractes antiquus Marsh, sp. nov. 
Among the other bird remains in the Museum of the Phil- 
fdelphia Academy, is a very perfect left humerus fom Tar- 
oug Ye 
mineralization render it extremely probable, at least, that it is 
from the Tertiary deposits of that region. This humerus — 
the same transverse obliquity which characterized the s 
just described, and so strongly resembles in other respects also 
the same bone in the reese t it should evidently be referred 
to that family. It approaches most near! the humerus of the 
Guillemots, especially those now included in the genus Catar- 
. 
