152 



SATJKOPTERYGTA. 



dividing the ventral from the dorsal portion, and are thus more of 

 the type of Thaumatosaurus. Pelvis (figs. 53, 54) like that of 

 Pliosaurus, the pubis and ischium uniting to form an obturator 

 foramen. Relative lengths of humerus and femur unknown. 

 Humerus articulating distally with only the radius and ulna, which 

 are relatively short, and separated only by a small interval (fig. 52) ; 

 ulna and fibula subreniform, the former being considerably the 

 larger of the two. 



This genus may have been directly derived from the Longiros- 

 trine group of Plesiosaurus. 



Fig. 49. 



Peloneustes philarchus. — Dorsal aspect of the coracoids ; from the Oxford 



Clay of Bedford. Reduced, gl, glenoid cavity. 



(This and the preceding figure from the ' Quart. Joum. Geol. Soc.') 



Peloneustes sequalis (Phillips 1 ). 



Syn. Pliosaurus cequalis, Phillips 2 . 

 Pliosaurus sterrodirus, Seeley 3 . 



Imperfectly known. Cervical vertebrae with the neural canal 

 •sunk into the centrum, and the " pectorals " with distinctly concave 

 terminal faces. Larger than typical examples of the next species. 



This species was founded upon a femur (fig. 50) from the Kime- 

 ridge Clay of Oxfordshire, which so closely resembles the corre- 

 sponding bone of P.jihilarchus as to indicate its generic identity ; the 



1 Geology of Oxford, p. 365 (1871). — Plesiosaurus. 2 Loc. cit. 



3 Index to Ayes &c. in Cambridge Museum, p. 98 (1869). — No description. 



