42 FIELD CoLuMBIAN MusEuM—GEo ocy, VoL. II. 
to the base of the dorsal ramus, throughout the whole extent of the 
concave portion of the border. The bone differs from the scapula 
of Murenosaurus* in the less expanded ventral ramus,which is sepa- 
rated from its mate by the clavicle and episternum. From the CryA/o- 
clidust scapula it differs in having a more slender and elongate dorsal 
ramus, and in the non-expansion of the ventral ramus. From a 
scapula of Pl. mudget Crag. from the Lower Cretaceous in the 
University of Kansas Museum, it differs in its much less slender 
coracoidal and dorsal rami. The bone is also much more slender 
than in Peloneustes. (See Pl. XII.) 
The coracoid is a very large and broad plate, with a slender, 
blade-like epicoracoid projection. Its glenoid portion is massive, 
with a smaller humeral articular surface, and a larger scapular facet, 
meeting each other in a very obtuse angle. The external border is 
thickened and concave, produced into a considerable projection at 
the posterior angle. Just before its termination there are several 
tooth-like projections of small size, evidently for muscular attach- 
ment. The posterior margin is thin, with rounded angles anda slight 
concavity between them. Opposite the glenoid articulation the bone 
is Massive, meeting its fellow in a thickened bar with an oblique 
sutural surface. Immediately posterior to this interglenoid thicken- 
ing, the bone on the mesial side is very thin, and in the anterior part 
of this thinned portion, near the middle line, there are two large, 
well-defined, round foramina that have never before been described 
in the coracoid, though perhaps indicated in the description of 7y7n- 
acromerum. The clavicular or epicoracoid process in front is long 
and thin, with nearly parallel sides, the anterior end slightly expanded 
and its margin with a cartilaginous border. The sutural surface for 
the clavicle extends back on the upper surface to nearly midway of 
the process. The coraco-scapular foramen is elongate in shape and 
is bounded entirely by the two bones, save for a short distance at the 
front inner part where the clavicle completes the margin. The cora- 
coid has the posterior outer angle more produced than in either 
Cryptoclidus, Peloneustes or Murenosaurus, and the clavicular process 
is longer and better developed than has been described in any form, 
except perhaps in 77inacromerum. 
‘The clavicle is a thin, concave, irregularly triangular or triradi- 
ate bone, and is well developed. It lies upon the ventral plate of the 
scapula and the epicoracoid process of the coracoid, and above the 
squamous margin of the episternum, a remarkable position for a_ 
* Andrews, Ann. Mag. Nat. His. xv, 431. 
+Andrews, Ann. Mag. Nat. Hist. xv, 355. 
: S 
. 
- 
ss 
