E 
WILLISTON: RESTORATION OF ORNITHOSTOMA (PTERANODON). 43 
ahalf inch. It is of considerable thickness, and may be for the 
attachment of the stout co-ossified rib attached to the first of the 
consolidated dorsal vertebra. The lateral margins of the sternum, 
back of the angle, are thin, and have three emarginations, separat- 
ing four articular projections. The three posterior ones are small 
and pointed, and could have given attachment to only slender ribs. 
The lateral borders are parallel with the longitudinal axis of the 
bone. The posterior border is not preserved, but from the gen- 
eral resemblance to the bone in Myetodacty/us, | believe that it is 
nearly straight, although it may have been gently concave or 
convex. ‘The bone was in all probability concave above in life. 
Length of presternal projection in front of articulations. 44 mm. 
Diameters on COrdcOidarMcwlanomot nation Vesey abe 
WAC EAS OR DENS can sektoih Siersmnul si bak elt a ALON AAs MONA eed 
IDET RHMOt Omen Wily ace Sites vinmatn a Wrst mek resp Vania an rT ta.) 
emo thvOn Matera Mar OS yer Cue e vic silo, Neri, tea eG iyiS 
Length of anterior oblique margins from coracoid artic- 
AITO OCR CAC Uaoe ONY sUamiv ta MA WG ANNUAL Ces tah GON ee RAMEE RoE 
Coraco-scapula. 
This bone is stout, U-shaped, with the coracoid arm distinctly 
longer than the scapular. The distal extremity of the scapula has 
a large oval facet placed obliquely to the long axis, and evidently 
also obliquely to the transverse axis of the body, indicating that 
the bone was directed not only outward and downward, but also 
more or less forward. The shaft in all the known specimens below 
the articulation is trihedral or flattened, but in life it was evidently 
round or oval in cross-section. On the lower part the width. is 
Sreater, due to a projection of the dorsal side before the glenoid 
articulation, for the attachment of muscles. ‘The glenoid articula- 
tion is deeply concave from above downward, convex from side to 
side and bounded both above and below by a prominent ridge, that 
On the inferior border being much stronger than the upper one. 
The surface is markedly oblique to the plane of the bone, doubtless 
in life directed outwardly and posteriorly in the oblique position of 
the bone that I have described. The surface is considerably 
Narrower from side to side below than above, and in this direction 
it is convex throughout. A rugose line, indicating the junction 
of the two bones, passes directly backward near the middle of the 
articular surface. At the bottom of the U, formed by the conjoined 
bone, there is a process arising from the scapula and reaching to 
the anterior surface of the coracoid, to which it is joined; it in- 
