20 Watson, Nezv Genera of Upper Liassic Plesiosaurs. 



inner side of the scapula. This tag is more than a centi- 

 metre thick ; of the thickness of the rest of the bone 

 nothing can be said. 



Pelvis. 



With the exception of the ih'a the pelvis is naturally- 

 articulated ; it is exposed from the ventral surface. 



It is remarkably broad and sturdy. 



Pubis. The pubis is a squarish plate of bone whose 

 thickness cannot generally be determined ; it meets its 

 fellow of the opposite side in a long symphysis. In the 

 region between the acetabula the symphysial face must 

 be very deep ; for there is in this region a pronounced 

 ridge across the bone. 



The anterior edge is thin and shows a small notch, 

 of a type which is quite common in the Sauropterygia 

 and is apparently associated with some attachment of the 

 plastron. 



The exterior border of the bone is not well shown but 

 cannot differ more than a {&\n centimetres from that given 

 in the figure {Text-fig. VI.). The acetabular face is large, 

 some lo cm. long and 5 cm. wide, the face opposed to 

 the ischium is however very small, being less than 5 cm. 

 long. The posterior border presents the usual concavity 

 to the obturator foramen, and at the median end is in 

 contact with the ischium. 



Ischium. The ischium is of the usual hatchet-shape. 

 The head is obliquely set on so that the posterior end of 

 the bone must have pointed down during the life of the 

 animal. It has the usual three facets, that for the ilium 

 being somewhat obscurely marked off from the acetabular 

 face. 



The blade of the bone is thin and there is no long 

 median symphysis in the middle line. Although the 



