210 THE ANATOMY OF VERTEBEATED ANIMALS. 



Fi? 68. 



A 



Tm^ 



Ph. 



Fig. 68. — Diagram showing the structure of the most important parts 

 of the skeleton of Plesiosaurvs. — A, the skull : JVa, nasal aperture. — 



B, the left fore limb : H, humerus ; U, ulna ; JR, radius ; r. i. u., 

 radiale, intermedium, and ulnare, in the proximal row of carpal bones 

 1, 2, 3, distal carpal bones; 3Ic, metacarpus; P/i, phalanges. — 



C, a dorsal vertebra with ribs (iJ.), and ventral ossifications ( V.o). 

 — D, the left hind limb : F, femur ; T, tibia ; F, fibula ; t. i.f., tibiale, 



