720 SHUFELDT—OSTEOLOGY OF THE STRIGES. [Dee. 7, 
EXPLANATION OF PLATES. 
[ The figures in these Plates are all reproductions of photographs made direct 
from the specimens by the author, represented by material either in his own private 
collection or in the collections of the U. S. National Museum at Washington, D. C., 
U.78: As] 
PLATE X. 
FIG. 1. Basal view of the skull of a nestling Great Horned Owl (Budo virginianus). 
Mandible articulated, but a number of the bones of vault of cranium and face 
removed. Maxillaries and maxillo-palatines somewhat displaced. Natural 
size. Specimen in the author’s collection, and taken for him by Dr. W. S. 
Strode, of Bernadotte, Ill. The nestling was just quitting the nest. 
FIG. 2. Basal view of the skull of nestling Budo virginianus. Belonged to the same 
clutch as the one in Fig. 1, and has the same history. Natural size and shows 
how these birds vary in the matter of proportions when hatched nearly at the 
same time. Figs. I and 2 show well the sutural lines at the base of the cranium. 
FIG. 3. Outer aspect of the right pelvic limb of the nestling Budo virginianus. 
Natural size, and from the same specimen to which the skull shown in Fig. 2 
belonged. This specimen exhibits very well the ossific centres and develop- 
ment of the epiphyses about upper part of the ankle-joint. 
Fic. 4. Palmar aspect of the right pectoral limb of the nestling Budo virginianus. 
Natural size, and from the same specimen to which the skull shown in Fig. 2 
belonged, as well as the pelvic limb in Fig. 3. The humerus and distal pha- 
langeal digit are somewhat turned aside from their normal positions. 
PLATE XI. 
Fic. 5. Right half, internal view of the skull of an adult specimen of the Great 
Horned Owl (Budo virginianus). Natural size and showing comparative pro- 
portions of brain cavity, the amount of diploeic tissue and other structures. 
Mandible removed, but quadrate and pterygoid zm sétu. (Spec. No. 17139, Coll. 
U.S. Nat. Mus.) 
Fic. 6. Left half, internal view of the skull of Budo virginianus, Natural size and 
from the same specimen as shown in Fig. 5. 
Fic. 7. Superior aspect of the skull of an adult specimen of the Great Horned 
Owl (Budo virginianus). Natural size and the mandible removed. From an 
unnumbered specimen in the Collection of the U. S. National Museum. 
PEATE Xd. 
Fic. 8. Basal view of the skull of an adult specimen of the Snowy Owl (ycfea 
nyctea). Natural size and with the mandible removed. (Spec. 18458 of the 
Coll. of the U. S. Nat. Mus.) 
FIG. 9. Dorsal aspect of the pelvis and three anterior caudal vertebrze of an adult 
specimen of the Hawk Owl (Scotiapex cinerea lapponica). Natural size and 
from a specimen in the author's private collection; it having been presented to 
him by Mr. Ernest Seton-Thompson, who collected it near Toronto, Canada, in 
May, 1890. 
Fic. 10. Left lateral view of the skull and mandible of an adult specimen of the 
Great Horned Owl (Bubo0 virginianus). Natural size and the same skull as 
shown in Pl. XI, Fig. 7. 
