OSTEOLOGY OF RHAMPHOCOTTUS 471 



The two large inferior pharyngeals (i. ph.) are united along 

 the median line and lie in the floor of the pharyngeal cavity im- 

 mediately posterior to the fourth pair of eeratobranchials. They 

 are triangular in shape and their superior surfaces are covered 

 with strong villiform teeth (fig. 12). 



6. Shoulder and pelvic girdles 



The supraclavicle (sol.) is a flat, elongated bone, the superior 

 end of which is expanded into an angular process which bears 

 two rounded processes for articulation with the under surface 

 of the posttemporal. The inferior and more flattened part of 

 the bone is attached to the superior surface of the clavicle (fig. 

 10). 



The clavicle (cl.) is a large bone of very irregular form. It. 

 extends upward and backward frorii the angle of the mandible 

 to a point just posterior to the posttemporal and almost directly 

 beneath the occipital spine. The upper end is wide and broadly 

 forked, the lower limb extending backward as a prominent sharp 

 spine. Centrally the bone narrows considerably, but inferiorly 

 it again broadens into a wide delicate lamina which curves about 

 on itself to form free dorsal and ventral wings (figs. 4 and 10). 



From the under surface of the superior end of the clavicle the 

 long, slender, and flat postclavicle (pel.) passes posteroventrally 

 into the lateral body wall for a considerable distance {pel., figs. 

 4 and 10). 



The upper ann of the hypercoracoid (hpc.) is pierced by a 

 large foramen. Below the foramen the bone is lamina-like and 

 lies closely against the clavicle. 



The hypocoracoid Qipoc.) is a wide irregular bone joined 

 closely to the posterior margin of the clavicle without the inter- 

 vention of foramina (fig. 10) . 



Three or four wide, lamina-like mesocoracoid (mc.) bones oc- 

 cupy the wide space between the actinosts, hyper- and hypo- 

 coracoids. Their exact number could not be positively deter- 

 mined because of their membranous character and their indefinite 

 boundar}^ lines (fig. 10). 



