1888.] ANATOMY OF THE MESOSUCHIA. 429 



(c) an anterior compressed portion, of which the edge is rough 

 and suggestive of synchondrosial junction with the coracoid. This 

 is separated by the notch from the prsescapular or acromial process. 



Coracoid (fig. 2, p. 428). — This is a flattened bone with a con- 

 tracted middle and expanded crescent-shaped ends. The sternal end 

 is undivided ; its outline is an arc the chord of which is 40 mm. in the 

 right and 42 mm. in the left scapula. The dorsal or scapular 

 extremity exhibits posteriorly a stout subtrihedral articular portion, 

 the glenoid complement {g) ; and anteriorly a thin rough margin for 

 union with the scapula (s). Opposite the junction of these two 

 parts, the coracoid is perforated by a large submarginal foramen. 

 The anterior and posterior borders of the coracoid are deeply concave, 

 the former most so. 



Humerus (Cat. No. 30). — The right humerus, although flattened 

 and fractured by compression subsequently to death, shows very 

 well the form of this bone. The proximal end bears a long oval 

 articular surface, situated almost entirely behind the long axis of the 

 shaft, convex in both directions from the dorsal or extensor to the 

 ventral or flexor aspect, and also from the radial to the ulnar border. 

 The radial border inclines forwards for a space of 22-5 mm., and 

 beyond this it curves slightly inwards towards the axis of the bone, 

 thus, by chani;e of direction, forming a salient (deltoid ?) crest ; 

 beyond this it passes in a nearly straight line nearly parallel to the 

 posterior border to the distal end of the bone. The posterior or 

 ulnar border is first concave near the proximal end, and thence 

 nearly straight to the distal end. On the dorsal surface in its 

 proximal half is a rough axial swelling, from which the surface 

 declines towards the radial and ulnar borders. The ventral or under 

 surface is sinuous, being gently convex in the direction of its long 

 axis and concave in the preaxial portion, corresponding to the deltoid 

 crest. The distal end shows the usual condylar division. 



Dimensions. millim. 



Length 57 



Proximal articular surface, long axis 16 



„ „ ,, short axis 7 



From proximal end to deltoid angle 23 



Breadth at deltoid angle 21 



Breadth midway between angle and distal end . . 13 



Breadth at distal end 14 



Pelvic Girdle (the sacrum is already described). 



Ilium (Plate XIX. figs. 1, 2). — ^This is a flat roughly quadrilateral 

 bone. The acetabular hollow (a) is shallow ; its upper limit is indis- 

 tinct. Its lower border presents two synchondrosial surfaces separated 

 by a low prominence. Of these, the posterior {p.i) is stout and trihe- 

 dral ; it projects at the junction of the inferior and the posterior 

 border. The anterior of the two synchondrosial surfaces {a.i) is 

 compressed and of oblong figure. Both articulated with the ischium, 

 the posterior directly, the anterior doubtless by the interposition of 



Pkoc. Zool. Soc— 1888, No. XXX. " 30 



