23 
Osteological Studies of the Subfamily Ardcinec. 
tionately enlarged. It grows gradually smaller, however, as we 
■descend, being of the least calibre in the lower third, when it 
again enlarges transversely to support the troehleae for the 
digits. The upper half of the bone is flat both posteriorly and at 
the lateral aspects. In front it is longitudinally excavated down 
the middle, beginning where it is the deepest, just below the inter- 
condyloid tubercle. These surfaces are exchanged for the sub¬ 
elliptical shaft as we gradually pass to its lower half, the major 
axis being*transverse. 
At the base of the excavation above, a few millimetres below 
the anterior crest of the summit, we find the shaft pierced by the 
foramina, placed side by side. The innermost and larger one of 
these passes rather obliquely through the the bone to make its ap¬ 
pearance, rather larger in size, just inside of the hypotarsus. 
Considerably smaller, its companion pierces the tarso-mar- 
tarsial shaft, still more obliquely downwards, to make its exit as 
a foramen of diminished calibre on the opposite side of the hypo- 
tarsus. The posterior opening of this latter one is seen in Figure 
15 - 
• Viewed from in front, the troehleae present the following 
points for examination : the mid one extends the highest on the 
shaft, and projects beyond the others anteriorly. It is distinctly 
grooved down its middle, and descends the lowest. The inner 
one is the broadest and is perfectly smooth in front, being but 
slighly grooved behind, while the other two are decidely so. Fi¬ 
nally, the outer troehleae is also smooth in front, and does not 
descend as low as either of the others. Between this one and the 
next the usual foramen pierces the bone, low down in the groove 
between them. 
It will be seen that these troehleae are so placed as to 
be slightly convex forwards, and in a less degree concave 
behind, where they come up to nearly the same points on the 
shaft, the middle one being rather the lowest. Moreover, the 
mesial grooves that mark them are here carried up to their very 
terminations. This posterior aspect of the distal extremity also 
shows the foramen for the anterior tibial artery in full view, above 
these troehleae, and on the inner side above it, a circular facet for 
the first metatarsal. 
These three long bones of the pelvic extremity of Ardca hero- 
dias have the following measurements in the adult: the femur, 
