SKELETON OF PHORORHACOS INFLATUS. 69 
The proximal end of the bone is peculiar. The acrocoracoid is almost completely 
absent, the upper end of the bone rising scarcely at all above the scapular surface. 
From the acrocoracoid region a ridge runs down the antero-internal border of the bone 
and forms the inner wall of a deep channel, which is bordered externally by the 
prominence formed by the surface for the scapula and the small procoracoid process. 
On this descending ridge there is, at some distance from its upper end, an elongate flat 
facet with which probably the clavicle articulated. 
The surface for the scapula is a large, deeply concave area, nearly circular in outline ; 
below its internal border arisesa small process or hook of bone (broken in the specimen 
figured), which overhangs the groove above described and is the procoracoidal process. 
The glenoid surface is a smooth, slightly convex area, the lower border of which 
forms a prominent overhanging lip on the postero-external side. 
The coracoid just described is one of the most remarkable bones of the skeleton. 
Its extreme elongation and the peculiar structure of its upper end, particularly the 
almost complete suppression of the acrocoracoid, are paralleled, so far as I am aware, 
only in the coracoid of the flightless Aptornis. The coracoid of this bird differs, 
however, in several important particulars, e.g. in the large size of its procoracoidal 
process, the presence of a supracoracoid foramen, and in the complete fusion of the 
lower extremity with the sternum. 
Fiirbringer has regarded the absence of the acrocoracoid as diagnostic of the Ratite, 
and has suggested that the term “ Platycoracoidee” should be used for them in 
contradistinction to the Acrocoracoidee, or Carinate. The oceurrence of this 
character in two such distinctly Carinate types as Aptornis and Phororhacos, however, 
invalidates this distinction, and tends to show that the presence or absence of the 
acrocoracoid, like that of the keel of the sternum, is in some way dependent on the loss 
of flight, and probably also on the increase in the bulk of the body. 
The articulation with the sternum is particularly well developed, and in no bird could 
the prominent tubercle and shelf above described be found developed to the same 
extent. No trace of the sternum is preserved, but, judging from the coracoids, it was 
probably of considerable size. 
Scapula. (Plate XVII. fig. 2.) 
Of the scapula no perfect specimen is preserved, but the most complete, here figured, 
wants the distal portion of the blade only. ‘The surface for union with the coracoid is 
highly convex and roughly circular in outline; it is much roughened, and the union of 
the two bones must have been a very close one. ‘The glenoid surface, which is slightly 
convex, is raised on a prominence which projects considerably below the inferior border 
of the blade, ‘here is a very large acromium process. ‘The portion of the blade 
preserved is somewhat rounded externally and flat internally. 
The width of the proximal end of this bone is 30 mm. 
