File:The Quarterly journal of the Geological Society of London (13205121223).jpg

ANNIVERSARY ADDRESS OF THE PRESIDENT. 59
submit, then, that the evidence of a dorsal extension of the scapula in
Plesiosaurus is irrefragable. With regard to its presence in Plio-
sauras, whilst I do not see any reason to doubt it (for analogy
Fig. 15. — Plesiosaurus clolichodeirus. (From a cast in the
Geological Society's Museum.)
per, the praecoracoid ; sc, the scapula ; cor, coracoid ; /, foramen
H, the humerus ; gl, the glenoid fossa.
would lead one to expect it), I find in the British Museum only two
specimens bearing on the question, and cannot learn of the existence
of others. They are a pair of scapulae associated with a trunk-
vertebra and ribs assigned to Pliosaurus planus, Owen, and the
very fine, almost perfect, shoulder-girdle, a dissociated fossil, pur-
chased some years ago, I think, of Mr. Charlesworth, and referred to
Pliosaurus, sp. inc. (fig- 16). The generic identification of these two
fossils with Pliosaurus being, as I submit, non-proven, they cannot
afford decisive evidence of the form of the scapula in this genus. On
the other hand there is unimpeachable evidence that Plesiosaurians
of the Elasmosaurian pattern, as Colymbosaurus, long- necked and
therefore certainly not Pliosaurian, had a scapula sending off
41 dorsad and laterad " such a blade or process as was ascribed by
Prof. Owen to Pliosaurus, and represented by him in his figure of
the " sterno-coraco- scapular frame," -which it is believed was sug-
gested by the fossil Xo. 46833 in the British Museum. With respect
to Pies. Manseli, since its coracoids resemble those of No. 46833,
analogy justifies the inference that there is a corresponding agree-
ment of the scapulae.
Another generic character of Pliosaurus, found by Prof. Owen
in the junction of the anterior recurved part of the (praecoracoid)
scapula (Ow.) with the narrow anterior praeglenoid part of the cora-