6 Watsc~)N, New Genera of Upper Liassic Plesiosaiirs . 



across : it is here of nearly the same depth. The proximal 

 end presents two triangular facets, both at their maximum 

 six centimetres deep, the inner seven centimetres long for 

 attachment to the coracoid, the other, which forms part of 

 the glenoid cavity, only five centimetres. The dorsal 

 ramus is a plate of bone 85 cm. long, 55 cm. wide in 

 the middle, and having a maximum thickness of just 

 under 2 cm. It rises from the joined posterior and 

 anterior rami at their outer edge, and is directed dorsally, 

 backward and outward, with its greatest breadth parallel 

 to the axis of the animal. 



The anterior ramus is confluent with the posterior and 

 dorsal rami ; it forms a broad plate of bone joining its 

 fellow of the opposite side in the middle line, and passing 

 backwards as a strong bar to meet the anterior projections 

 of the coracoids ; this bar, formed by the two coracoids 

 and scapulae, is of triangular section, the flat dorsal face 

 being five centimetres wide, and the depth of the bar 

 being some six centimetres. The anterior rami of the 

 scapulae, are not in the same plane as the corresponding 

 coracoids, but are raised anteriorly so as to make the 

 whole anterior part of the arch convex from front to 

 back when viewed from below. The anterior rami, of 

 course, meet at an angle so that the whole girdle is 

 concave from side to side. 



The two pre-coracoidal foramina are 10 cm. long by 

 6 cm. wide, and the plate of the anterior ramus of the 

 scapula in front of them is at least 8 cm. from front to 

 back. 



Clavicles. The left clavicle is completely preserved 

 with the exception of its anterior edge, which is slightly 

 injured. 



It is a thin bone with sharp edges, very tightly fitted 

 on to the visceral surface of the anterior ramus of the 



