10 
convex anteriorly, and concave posteriorly, where it is extended upon a short posterior 
process, forming the squamosal cup ; the inner and smaller facet is convex, and above 
this is the pterygoid tubercle. 
The lower tympanic condyles are adapted to two corresponding cavities on the 
articular part of the mandibular ramus, which developes behind them a vertical trian- 
gular surface, the outer and inner margins of which are produced into criste, There 
is a small coronoid process external and anterior to the outer articular surface. The 
surangular part of the ramus shows an oval vacuity, about 3 lines by 2 lines; the groove 
defining the surangular from the angular part widens as it advances, and leads to an 
oblong fissure between the surangular and dentary elements. 
The splenial element retains its distinctness posteriorly, and a groove upon the lower 
margin of the ramus indicates the extent of its forward production: the posterior limits 
of the posteriorly bifurcate dentary element are clearly defined. The right and left of 
these elements coalesce to form a compressed, pointed symphysis, 1 inch long, half an 
inch deep at the back part, gradually contracting forwards to a point, with a grooved 
upper surface; the upper margin of the symphysis is slightly convex lengthwise, the 
under margin slightly concave lengthwise. 
The outer surface of the symphysial part of the jaw is roughened by numerous small 
perforations and grooves, indicating the vascularity of the periosteum in connexion with 
the reproductive matrix of the horny sheath of the beak: the tip of the premaxillary 
has a similarly sculptured surface. 
The basihyal, including the urohyal, is 10 lines in length ; the fore end of the basihyal 
is slightly expanded, and occupied by a trochlear articular surface, convex transversely, 
concave vertically. The bone again expands to form the pair of concave oval articular 
facets for the thyrohyals, beyond which it is continued as a slender pointed style 
(urohyal) for about 4 lines; the part anterior to this is the true basihyal. The thyro- 
hyals (hyobranchyals) are slender, slightly bent styles, 2 inches long, swelling into a 
small knob at both ends, the one articulated to the basihyal being rather the largest. 
§ 3. Scapular Arch and Appendage. 
The bladebone (PI. I. fig. 1, 51), 3 inches 8 lines in length, extends backward to the 
ninth rib, gradually expanding vertically and more quickly flattening laterally to its free 
extremity, which is truncate obliquely from above downward and backward. The 
proximal end has opposite dimensions, being much expanded laterally or transversely 
to the axis of the trunk, and narrowest vertically ; it presents a broad transverse 
condyle, which is a little expanded at each end, to the coracoid. The outer end is the 
broadest; the inner one the most produced. The shaft of the scapula quickly con- 
tracts to a transverse diameter of 3 lines, and then begins to grow thin and broad, 
but as if with a kind of twist, the inner or medial border near the head of the bone 
