FEOM THE TEIAS OP LOMBAKDT. 



Immediately behind the pectoral arch begins the series of small bones which form 

 the plastron ; this does not differ from that of the other Nothosaurians the plastron of 

 ■which is known. 34 transverse series of bones can be counted between the pectoral 

 and pelvic arches, each series consisting of a median angulate piece and two straight 

 ones on each side (fig. 3), as in Plesiosaurs ^, which reptiles lack, however, the angular 

 bend of the median piece. 



Kg. 2. 



Kg. 3. 



Posterior cervical rib. 



Anterior plastral bones. 



It is to be regretted that the dislocation of the pectoral arch renders the recognition 

 of its elements somewhat difficult. There is one bone as to the nature of which no 

 doubt can be entertained : that is, the right coracoid, lying on the inner side of the 

 right humerus, which agrees essentially with the same element in Neusticosaurus. It 

 is nearly equally expanded at both extremities, its width somewhat exceeding half its 

 length, which nearly equals that of the humerus ; its inner border is shorter and more 

 concave than the outer. Two large, flattened, curved bones anterior to the coracoid I 

 take to be clavicles, the left of which appears to cover the left coracoid, and is separated 

 from the other coracoid by a small bone with concave surface, which is probably the 

 proximal (acromial) portion of the scapula. Two displaced anterior dorsal vertebrse 

 and a rib are exposed between the coracoids. 



Only the right humerus is completely exposed, having slipped out of the glenoid 

 cavity. It is a short, stout, curved bone with strong preaxial crest ; it is provided with 

 a small, elliptic, entepicondylar (ulnar) foramen ; its length is exactly half that of the 

 skull. The distal extremity of the left humerus projects from below the left clavicle, 

 showing distinctly the epicondylar foramen. For the other bones of the fore limb we 

 must turn to the left side of the specimen, where the whole forearm and manus are 

 exposed in natural juxtaposition, the radius overlapping the proximal extremity of the 

 ulna. The radius is large and much flattened, with concave inner border, its length 

 twice its distal width and half the length of the humerus ; the ulna is much more 

 slender. The carpal bones are seven in number : a large intermedium, a radiale, and 



^ Mr. C. W. Andrews has recently pointed out (Geol. Mag. 1895, p. 243) that some Plesiosaurs have three 

 ■paired bones to each row. {June, 1805.] 



