EXPLANATION OF PLATES. 763 



m internal pterygoid bone; r, superior maxillary bone with a 

 poison-tooth in use, and another in the living animal con- 

 cealed in the gum and turned backwards, which, when the first 

 falls out, is destined to take its place. 



Fig. 5. Bight superior maxillary bone of Najcu tripudians, p. 263; 

 b and r, as in the preceding figure. 



Fig. 6. Anterior part of the bony head of Python molurus, p. 277; 

 b, anterior frontal or lateral ethmoid bone; t, nasal bone; q, 

 intermaxillary bone; r, superior maxillary bone; , attached 

 to it, the anterior extremity of the external pterygoid bone. 



Fig. 7. Skull of Dipsas dendrophila, p. 266, seen from above; a, a, 

 frontal bones; b, b, anterior frontal bones or lateral ethmoid 

 bones; f, parietal bone; g, g, ossa mask/idea; k, &, quadrate 

 bones ; t, t, nasal bones ; w, lower jaw. 



Fig. 8. Right upper jaw-bone of the same species, the posterior tooth 

 is grooved. See this last magnified, Fig. 8 a. 



Fig. 9. Left upper jaw of Python molurus (see fig. 6) seen from below; 

 m, r, as in fig. 4 ; n, palate-bone. 



Fig. 10. Skull of Amphisbcena alba, p. 281 ; k, as in figs. 4 and 7. 



Fig. 11. The anterior extremity of the skull of a Caiman, Crocodilus 

 sclerops (p. 315) after Cuv. Ann. du Mus. x. PL i. fig. 16; *, 

 fourth tooth of the lower jaw, of which the apex is received 

 in a cavity of the upper jaw. 



Fig. 12. Skull of the Gavial, Crocodilus gangeticus, p. 316, after Cuv. 

 Ann. du Mus. xii. PI. i. Fig. 6; a } a, intermaxillary bones; 

 b } b } superior maxillary bones; c, c, malar bones; i, i, lachry- 

 mal bones ; h, h, anterior frontal bones ; h', h', posterior frontal 

 bones; H, proper frontal bone; m, parietal bone; between it 

 and the frontal bone are seen the large round apertures which 

 distinguish the skull of the crocodiles, and especially of the 

 gavials from that of the caimans; through these apertures 

 are seen the internal pterygoid bones f, f; n, n, squamous 

 bones (ossa squamosa), mastoi'ds OWEN. Figs. 11 and 12 are 

 reduced. 



Fig. 13. Skull of a young Crocodilus bipoi'catus (p. 31o), *, fourth tooth 

 of the lower jaw which is received in a notch on the outer 

 margin of the upper jaw. In the lower jaw is seen y, the 

 articular portion; x, the coronoid bone, surangular Ow. ; v, 



