30 



MAEINE EEPTILES OF THE OXEOED CLAT. 



fiat, roughly quadrate surface, making an obtuse angle with the head (h.) ; it is 

 situated towards the posterior edge of the upper surface. The posterior border of the 

 shaft is concave, except for the presence of a strong pointed prominence for the 

 attachment of a muscle (m.r.) ; the anterior border is less distinctly concave, the distal 

 expansion being much more developed postaxially than preaxially. The distal 

 surface bears two subequal facets, making a very obtuse angle with one another, for 

 the radius and ulna. Externally to these facets the anterior and posterior borders of 



Test-fig. 9. 



m.r. 



Imperfect fore and hind paddles of Sirnolestcs vorax: A, portion of right fore paddle from above ; 

 B, portion of left hind paddle from above. (E. 3319, about \ nat. size.) 

 f., fibula ; 7i., head of humerus and femur; int., intermedium ; l.p., tuberosity of humerus ; m.r., ridge for 

 the attachment of muscles : r., radius ; rad., radiale ; t., tibia; tr., trochanter; u., ulna; ida., ulnare. 



the distal expansion were probably fringed with cartilage. The radius and ulna (r. & u.), 

 though much flattened, are less shortened than in the Elasmosaurs. The radius (r.) is 

 a little the longer of the two ; its proximal end bears a flat straight surface for union 



