GILMORE: OSTEOLOGY OF BAPTANODON (MARSH) ital 
antero-posteriorly and is especially thickened on the posterior margins where it enters 
into the formation of the glenoid cavity. The articulating face for the coracoid joins 
this border at an obtuse angle. 
The scapula extends outward, upward and forward, not backward as Seeley sus- 
pected in his original description of the type of Ophthalmosaurus. Both arches before 
me have the scapulee retained in their natural relations to the coracoids and their 
position may be considered as absolutely determined. Viewed longitudinally the 
inner surface of the scapula is slightly concave, as it curves up to lap over the side 
of the ribs. On the upper free end the inner surface is quite flat, distally the articu- 
lating end is concave antero-posteriorly. The anterior border above is gently rounded 
but as it approaches the articular end it widens into a flattened oblique surface (x) 
that looks forward and upward. (See Pl. XIL., figs. 1 and 2.) 
Seeley * regarded a part of this border as the acromion process. ‘The oblique 
surface mentioned above is roughened and I have interpreted it as being the place 
of attachment for either the ligaments or cartilage which held the clavicles in posi- 
tion. The position of these elements is beautifully shown by a specimen of J. quad- 
riscissus, No. 6293, in the Stutgarter collection of which Frass* gives a figure. 
The scapulee of our specimens are not notched to fit over the articulating sur- 
faces of the coracoids as figured by Knight but unite by nearly straight articulating 
faces. An examination of Dr. Knight’s specimen, the type of B. marshi, convinces 
me that the articular ends of the scapulee of that species are not different than those 
of B. discus, but in the former case were crushed so that their true shape and rela- 
tions could not be accurately determined. The lower surface of the scapula is convex 
from end to end. Antero-posteriorly the free end is gently convex, but somewhat 
coneayve at the expanded articular end. Between the marginal ‘‘acromion process” 
and the articulation with the coracoid the internal border is especially compressed 
and remains free. 
Seeley has best described the humeral articulating border as follows: “The 
humeral articulation is an expanded triangular thickening of the bone, extending 
posterior to what would otherwise be an extension of the parallel sides of the free 
or distal end.” 
MEASUREMENTS. 
No. 878. Greatest width of free end of scapula. .......... 55 mm. 
CONG: sf COE CATGICU AbD Paces eneeceettedanesrcecectecee sett 3 
878. CO) Tenaya) CO READE penonsoonoosaancceesb00000 onobenscaddasnbodceHoaECes up 
Clavicles (cl.). —So far as 1am able to learn specimen No. 878 is the first Ich- 
“Seeley, H. G., Quart. Jour. Geol. Soc. of London, Vol. XXX., pp. 696-707, 1874. 
“¥Frass, E., lit. cit., Plate 1V., fig. 2. 
