722 GEOLOGICAL SURVEY OF THE TERRITORIES. 
ably connected with the sternum by corresponding pairs of costal ribs, 
the whole structure and appearance being distinctly oscine in char- 
acter. The vertebral ribs are very slender below and not so much ex- 
panded above as they are in some other birds. Commencing with the © 
last cervical rib, and continuing entirely through the dorsals, we find the 
series of epi-pleural appendages complete on either side, and freely artic- 
ulated with the posterior borders of the ribs, with which they make an 
angle of about 45°, and attain sufficient length to overlap the rib in their 
immediate rear, though often in younger birds, and even some old ones, the 
last uncinate process does not reach the free sacralrib. The sternal ribs 
are quite delicately fashioned, and support, as usual, anteriorly the trans- 
verse heads for articulation with the costal border of the sternum, while 
posteriorly we discern the moderately upturned and clubbed extremities 
with shallow facettes for the inferior ends of the vertebral ribs. 
The sternum of the Loggerhead Shrike is almost or quite typically 
‘‘eantorial” in itsoutlines, but only feebly pre-eminent in those features 
that stamp it as belonging to a bird of any great power of flight. The 
manubrium, directed upwards and forwards, springs from a solid base to 
become bifurcate at its anterior extremity and throw down a sharp 
border below, that becomes continuous with the carinal margin in 
front; the coracoidal grooves pass round laterally well beneath the 
costal processes, and merge into each other, mesiad, their point of meet- 
ing being denoted by an elliptical depression, at the base of which we 
occasionally find a single pneumatic foramen. The costal processes rear 
themselves upwards, forwards, and outwards, being broad but thin lam- 
ine of bone, impressed upon their posterior margins by the five trans- 
verse facetites for the sternalribs. The “body” is concave above, sloping 
to a shallow, osseous gutter, lying in the mesial plane directly over the 
keel; beyond, in this groove we observe a few scattered foramina for 
the admission of air to the more Solid structures of this confluent hemal 
spine. Behind, the bone is one-notched on either side, cutting out lat- 
eral processes with expanded posterior ends and a broad mid-xiphoidal 
portion—the direct continuation of the sternal body—(Fig. 92). The 
“carina” below averages about 7 millimeters at its deepest part; ante- 
riorly it protrudes as arounded carinal angle, from which point its inferior 
boundary sweeps backwards by a gentle convex curve to terminate in 
euch triangular space at the middle of the xiphoidal process 
seneath. : 
The sides of the keel present for examination well-defined subcostal, 
pectoral, and carinal ridges; the latter falls on either side from the base 
of the manubrial process to near the carinal angle, just within the bor- 
der, and sometimes has a thickened backward branch starting from its 
lower end. The confluent pelvis, in common with the majority of pas- 
serine birds, has that strikingly angular outline, due largely to sharpened 
borders and outstanding spiny processes. There are ten vertebre in 
its ‘*sacrum,” all unusually firmly fused together, vacuities only occa- 
sionally occurring among the diapophyses of the ultimate few, three or | 
four at most. The pre-acetabular region of the ilia on either side is 
deeply concave, this concavity being carried up over the anti-trochanters 
to terminate in shallow grooves over the ischiatic foramina. The greater 
share of this surface looks almost directly outwards and only slightly 
upwards. The ilio-neural canals are divided by the confluent spines of 
the first four or five vertebree, they vary in width in different individuals, 
and terminate at points opposite the cotyloid cavities, at which point 
the neural spine suddenly becomes compressed, or rather annihilated, and 
the sacrum sustains a flattened surface to the ultimate boundary of the 
N 
