708 SHU FELDT—OSTEOLOGY OF THE STRIGES. [Dec. 7, 
ectocnemial is the shorter—that is, it does not extend so far down 
the shaft as the inner or procnemial. They have between them an 
ovate concavity, with the larger end above, the lower end subsiding 
upon the shaft with the ridges themselves. ‘The vertical elevation 
on the external aspect of the shaft for articulation with the fibula 
runs down the side but a short distance; a little below its abrupt 
termination may be observed, in a line with it, the nutrient 
foramen, entering very obliquely from above downward. After 
leaving the fibular ridge as far as the point where the bone begins 
to expand transversely at the distal extremity, the shaft is remark- 
ably smooth and nearly cylindrical. This transverse and distal ex- 
pansion is @hecked, both anteriorly and posteriorly, by abruptly 
meeting the distal condyles, the point of meeting perhaps being 
rather the higher behind. The condyles, differing but little in size, 
are singularly uniform as to shape, with their curved surfaces 
downward, being flat on their outer aspects, with a raised rim 
bounding them in each case. They stand out prominent and 
apart. Anteriorly their convex surfaces are the widest, behind they 
slightly approach each other, and the articular convex surface is 
narrowest on the outer condyle. ‘The intercondyloid notch is deep, 
and appears equaily well marked throughout its extent. Immedi- 
ately above it, anteriorly, there is a deep triangular depression ; 
another and more shallow one is found behind in the correspond- 
ing locality. Up the shaft a short distance on the inner side, 
anteriorly, is a little tubercle, to which is attached the ligament 
that binds down some of the strong tendons of the extensors. This 
ligament crosses the anterior triangular depression mentioned 
above obliquely, to be inserted near the external condyle superi- 
orly. This is the arrangement also in Budo virginianus, but in 
some of the Hawks this ligamentous bridge has become thoroughly 
ossified, forming a strong bony band across the concavity in ques- 
tion. It is interesting to remark here, however general the rule 
may be as applying to the diurnal and nocturnal Raffores, that 
whereas this band is ligamentous in thé tibia in some of the Owls, 
a bony one fuifilling the same function is found in them just below 
the head of the tarso-metatarsus ; these conditions are just reversed 
among some of the Hawks. Usually, in old birds of this species, 
the fibula is firmly united to the entire length of the fibular ridge 
of the tibia, a union almost amounting to anchylosis. Arching 
outward, its head, surmounted by an antero-posteriorly elongated 
