_ 1900.] SHUFELDT—OSTEOLOGY OF THE STRIGES. 719 
directly backward, as do also the ischia above them. Aside from the 
disproportion we see in the relative lengths of the bones of the leg of 
Speotyto, Micropallas has a skeleton of that extremity much as we 
find it in those birds. Its fibula is exceedingly slender and consid- 
erably shorter than the tibio-tarsus ; the arrangement and struc- 
ture of the podal joints of pes is bubonine. 
ON THE AFFINITIES OF THE UNITED STATES STRIGES. 
Regarding the Owls as a whole, the present writer considers 
them to be a group of nocturnal birds of markedly raptorial habits. 
Some of the species, however, are largely diurnal in their ways. 
They are not especially related to the Accifitres, but are, on the 
other hand, remotely allied with the Cafrvimulez. What we now know - 
of the structure of such forms as Sfeatornis and Podargus suffi- 
ciently indicate this much. 
Taking the Owls in our own avifauna, they may readily be 
grouped into two well-marked families—the Strygidz, to contain 
Strix, and the Budbonide, to contain all the other genera. Sfrix 
pratincola comes nearer the Cafrimu/gi than any other of our 
Strigine types. This is remotely suggested to us by the form of its 
sternum, the general aspect of the skull and a few minor points 
elsewhere in the skeleton. Of all the bubonine Owls we are inclined 
to think that Asio wilsonianus comes nearer Sfrix than any of the 
others. There is also doubtless an affinity among the genera 
Surnia, Speotyto and Micropallas. Bubo and Nyctea are strong 
types, with a great raptorial aspect in the cast of their skeletons, 
more especially in their beetle-browed skulls and their powerful 
raptorial feet. — 
_ Perhaps the asymmetry of the skull may also point to generic 
affinity, though it isa question; but if so, then Syrnium, Surnium 
and WVycta/a may be considered more closely related among them- 
selves than they are with any of the other genera. 
Megascops approaches Budo, and has a few characters, of light 
weight, in its skeleton that agree with the corresponding ones in 
Speotyto. 
