640 GEOLOGICAL SURVEY OF THE TERRITORIES. 
deep indentations of the xiphoid give rise on either lateral sternal bor- 
der to a long, stout process, extending backwards and outwards, with 
dilated extremity. 
The outer surface of the body of the sternum presents for examination 
well-marked pectoral ridges, and, running from the bases of the xiphoidal 
processes to the outer angles of the coracoidal depression, clearly defined 
subcostal ridges. 
The manubrium is a prominent, superiorly bifurcated, trihedral pro- 
cess, jutting out from a substantial base in the median plane, forwards 
and upwards, from the angle formed by the coracoid groove and the 
front border of the carina. At its base internally there is an extensive 
oval pneumatic foramen. Its bifurcations are rounded, and give attach- 
ment at their extremities to firm ligaments, that pass directly to the 
coracoidal capitula above. 
The groove for the coracotds is strongly marked and continuous in front, 
extending from costal process to costal process; its boundaries form the 
thickest and stoutest part of the bone we are describing. 
The costal processes, possessed of broad bases, arise as thin but prom- 
inent lamina, upwards, forwards, and outwards, terminated by flattened 
summits. Their posterior margins bear the costal facets for the articu- 
lating ends of the sternal hemapophyses. 
The sides of the body of the sternum on its ventral aspect make an 
obtuse angle with each other. The line of meeting in the mesial plane 
is quite evident; its anterior half is the seat of a row of various-sized 
pneumatic foramina. There are upon each costal border five, sometimes 
six, transverse facettes for the sternal ribs; the shallow depressions 
among them are scantily supplied with pneumatic foramina. 
The mid-xiphoidal border, in which the keel terminates posteriorly, 
is thickened; its other boundaries are sharp, with raised ridges below, 
just within their edges. The greatest length of the sternal body is a 
little more than two centimetres, and its greatest width a little more 
than one centimetre, the last measurement taken to the rear of the cos- 
tal processes. 
Sacral vertebra and ribs, pelvis, coccygeal vertebre—(P1. IV, Figs. 22, 
23, and 28).—The first sacral vertebra has become thoroughly confluent 
with the ossa innominata on either side and with the vertebra behind 
it. Its diapophyses seem to have spread out upon the under surface of 
the ilia, combining with them, for we observe that the first sacral pleu- 
rapophyses articulate in the ordinary manner with the transverse pro- 
cesses and the parapophyses, the tubercula being situated just near the 
outer iliac borders. This rib may become, as a rare event, confluent 
with the pelvis, but is usually free. Its hemapophysis is the longest of 
the series, and the articular facette on its lower extremity meets the 
last facette upon the sternal costal border. This sacral pleurapophysis 
may possess an epipleural appendage, though it seems to be the excep- 
tion. 
The second sacral rib is a delicate hair-like bone of uniform thickness, 
that does not show any decided tubercle, merely, after leaving the ver- 
tebra, coming in contact with the under surface of the ilium, on each 
side, for the entire interspace between the tubercle and head. It, too, 
may become confluent with the pelvis on its lower surface. 
Extending downwards and forwards by a gentle curve, it meets its 
hemapophysis through a miniature articulation. This latter style ar- 
ticulates along the posterior border of the sternal rib of the first sacral 
pleurapophysis, never reaching the costal border, and the second sacral 
rib never bears an epipleural spine on its posterior border. 
