PLATE I. 



Fia. Page. 



1. TTi/JxxJiis hasavHs, Egerton ; skull and mandible, right side view and (1 n) 



lower view, one-half nat. size, with a lower lateral tooth (1 ^) enlarged 

 twice. — Weald Clay ; Atherfield, Isle of Wight. The type specimen. 

 Museum of Practical Geology, London, no. 27973. a./., anterior 

 fontanelle ; ch., ceratohyals ; I., labial cartilages ; md., mandible ; 

 orb., orbit ; jj^g'., pterygo-quadrate (upper jaw). 6. 



2. Ditto; partially decayed skull and mandible, left side view, one-half nat. 



size, with the cephalic spine (2 a) nat. size. — AVeald Clay ; Cooden 

 Beach, Pevensey Bay, Sussex. Beckles Collection (B. M. no. 

 P. 11871). 7nd., mandible; 2^^'l-> pterygo-quadrate (upper jaw); 

 s., cephalic spine; ;r., cartilage at base of cephalic spine. 9. 



3. Hybodont Cephalic Spine; left side view, nat. size. — Wealden; Hastings. 



Eufford Collection (B. M. no. P. 6738). 14. 



4. Hybodont Cephalic Spine ; left side view and (4 <() hinder view, twice 



nat. size. — Wadhurst Clay ; Brede, near Hastings. Teilhard & 

 Pelletier Collection (B. M. no. P. 11895). 14. 



