110 MEMOIRS OF THE CARNEGIE MUSEUM 
ered rudimentary or wanting,’ must have been based upon a comparison of the 
coracoids of Bb. marshi with those figures of Ichthyosaurus which show the inter- 
clavicle as lying between these elements anteriorly. The portion of a girdle figured 
by him appears to be identical in form with the arches under discussion, one of 
which, No. 878, has a well developed interclavicle making it appear that Knight 
was mistaken in his interpretation of this region. 
Coracoid (co.).— The coracoids are broad subquadrangular bones that join one 
another medially by large elliptical facets. These facets are roughened and were 
evidently united by a heavy pad of cartilage, the width of which is best shown in 
Pl. XIL, figs. 1 and 2. : 
The internal or superior surfaces (Pl. XII., fig. 2), are flattened, though both 
elements are gently inclined toward the median line. The external or inferior sur- 
faces are concave transversely and convex antero-posteriorly. The lateral borders 
are especially thickened forming a heavy articular face for the scapulee and humeri. 
This outer articular end is divided into two unequal faces meeting in an obtuse 
angle. The more anterior and smaller one of the two is for the scapula, and looks 
outward, forward and obliquely upward. The larger and posterior surface forms 
the greater part of the glenoid cavity. It is very slightly convex from above down- 
ward and covered with tubercle-like eminences indicative of aheavy pad of carti- 
lage. This articular end is supported by a broad neck formed by a deep notch on 
the anterior margin and a slight emargination on the postero-lateral border of the 
coracoid. This anterior notch Seeley suggests, probably corresponds to the foramen 
found in the coracoids of the Dinosaurs. 
The anterior border from the inner notch thickens rapidly as it recedes poste- 
riorly to form the intercoracoidal facet (see Pl. XII., fig. 1). The posterior part is 
compressed to a thin plate, the border being rounded from the inner angle of the 
emargination to the median union of the two elements. 
The coracoids resemble those of the long-snouted species or Latipinnate form of 
Ichthyosaurs of which J. tenwrostris is a good example. 
MEASUREMENTS. ?*° 
No. 878. Greatest length of coracoid antero-posteriorly.....................++5 253 min. 
“ 878. cs width “ ss transversely ue 
oS SyIG) sf eee ee U0; =) grousonobdaonanopocodsanouDEccte 200 ‘ 
“* 878. us sc“ girdle end to end of scapule...................06+ 1 On 
Scapula (sc.). — The scapula is a moderately long bone, the upper half being nar- 
row with nearly parallel sides, the lower or articular portion is broadly expanded 
10 Measurements given of No. 878 are made from the right element, which appears to be the least distorted. 
