1 8 Watson, New Genera of Upper Liassic Piesiosaurs. 



The posterior ramus is broad, lo. cm. across at its 

 widest, and nearly 7 cm. thick ; in section it is triangular, 

 the broadest face being directed downwards, the other 

 two faces are of nearly equal size, the outer being some- 

 what smaller than the other. The outer border of the 

 bone is a marked ridge, owing to the concavity of the 

 corresponding face. 



The anterior ramus is a direct continuation of the 

 posterior one ; it also is of triangular section, but here the 

 ventral face is the smallest. The outer of the other faces 

 is nearly flat, whilst the inner is scooped out into a 

 roughened elliptical cup for reception of the clavicle. The 

 greatest height of the bar is over 6 cm., and its breadth 

 about 5 cm. 



From the dorsal ridge of the anterior and posterior 

 branches rises the dorsal ramus ; this is some 10 centi- 

 metres long, 6 wide, and 2 thick ; it is of oval section, and 

 is directed upwards and backwards, its length making an 

 angle of about 60° with the under surface of the posterior 

 ramus. Its breadth faces laterally. 



Clavicular Arch. The clavicular arch is seen from 

 below, and part of its right side is missing ; there is, 

 however, evidence for everything shown in the restoration, 

 including the width. 



The whole forms a large arc of a circle, probably 

 nearly a semi-circle, when complete. 



The interclavicle is a T-shaped bone, of which nearly 

 the whole stalk is bordered by the clavicles. Its anterior 

 border has a broad but shallow notch, and its posterior 

 border forms a rounded tag. 



The clavicle is suturally united to the external edge 

 of the interclavicle. Its general form will be seen from 

 the figure, but the most interesting character is a dorsally- 

 directed portion which fits into the depressed area on the 



