EXPLANATION OF PLATES. 763 



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

 poison-tootli 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. Right superior maxillary bone of Naja 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; 7', superior maxillaiy bone; I, attached 

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



Fig. 7. Skiill of Dvpsas dendrophila, p. 266, seen from above; a, a, 

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

 bones; ^ parietal bone; g, g, ossa mastdidea; k, k, quadrate 

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



Right upper jaw-bone of the same species, the jiosterior tooth 

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



Left upper jaw oi Python molurus (see fig. 6) seen from below; 

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



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



The anterior extremity of the skull of a Caiman, Grocod'dus 

 sderops (p. 315) after Cuv. Ann. du Mus. x. PI. 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 G-avial, Crocodilus gangeticus, p. 316, after Cuv. 

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

 b, b, superior maxillaiy 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 ai'e 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 

 hora.Q's, {ossa squamosa), mastoids Owen. Figs. 11 and 12 are 

 reduced. 



Fig. 13, Skull of a young Crocodilus biporcatus (p. 315), *, 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, 



