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- 

 coid, at the mesial and inner border of the coraco-scapular vacuity, 



