1906.] 



NATURAL SCIENCES OF PHILADELPHIA. 



477 



broad and convex. Lips thin. Teeth in jaws heavy, robust, and all 

 more or less smaller and of subequal size in upper jaw. In latter 

 arranged in an external approximated series of 5 on each side, and 

 each with a cusp at least, those most external with 3. Transversely 

 4 teeth connecting outer series, and tip of each with as many as 4 



^.-... 



Fig. 56. — Starksitia herniarius (Cope). 



cusps in most cases. Mandibular teeth arranged transversely across 

 front of mandible, 3 on each side, with cutting edges, each mth 1 

 cusp at least and each symphyseal with a large conic internal cusp. 

 External mandibular teeth small and inconspicuous, and posterior 

 dentary edges hard and rather sharp. Tongue a little elongate and 

 not free. Interorbital space broad and convex. Gill-opening for- 

 32 



