lo Watson, New Genera of Upper Liassic Plesiosaurs. 



the femur. The contour of the bone in the figure {Text- 

 fig. II.) is so arranged as to include the smallest possible 

 area ; the rough lines inside the bones show the shape of 

 the existing fragments. 



Ischia. The ischia are of the usual hatchet-shape, 

 thick at the proximal end, and forming thin plates of 

 bone where they join each other in a long median 

 symphysis. The acetabular end is remarkable for its 

 swollen character, it is not well exposed, but in one case 

 the usual three facets for the pubis, acetabulum, and ilium 

 are quite distinct. The neck of the bone is very slender. 

 The head is set on obliquely, so as to suggest that the 

 posterior ends of the ischia slope somewhat downwards, 

 and are not in the same planes as the pubes. 



The ischia and pubes do not meet in the middle line,, 

 so that there is only one obturator foramen. 



Ilia. The ilia are not definitely recognisable ; the only 

 thing which might be one is a mutilated bone lying on 

 the visceral surface of the coracoids. It is more than 

 15 cm. long, the shaft being round and about three centi- 

 metres in diameter ; the lower end is more than 7 cm. 

 across. Two fragments of a right ilium belonging to the 

 Northamptonshire specimen in the Manchester Museum 

 seem to agree closely with this bone. The shaft is at its 

 narrowest 27 cm. in diameter, and is very nearly circular ; 

 the upper part of the bone is thin, and 7*5 cm. from back 

 to front, and its upper border is at an oblique angle to 

 the shaft of the bone. The lower end is expanded, and 

 presents the usual two facets for the ischium and aceta- 

 bulum. 



This girdle reminds one strongly of the pectoral girdle 

 of the same specimen in its great relative narrowness. 



It differs markedly from that of Cryptocleidus, more 

 resembling that of Murcenosaurus : I believe, however,. 



