LIZARDS. 7 



may be characterized as Reptiles with the skin covered with scales 

 or tubercles ; with non-expansible mouth, the rarni of the mandible 

 being firmly united anteriorly by a suture ; with four or two limbs, 

 or at least rudiments of pectoral and pelvic bones; with teeth which 

 are ankylosed to the jaws, and not implanted in sockets ; with a 

 transverse anal opening. Movable eyelids and an ear-opening are 

 usually present. If the limbs are developed, they are generally 

 provided with five digits armed with claws; but as in some kinds 

 the limbs get weaker and shorter, the number of toes is gradually 

 reduced ; and there are Lizards in which the little limb terminates 

 in a single useless toe, or is even entirely toeless (see Fig. 2). The 

 tongue offers very remarkable differences in form and function. It 

 is simple, broad, short, soft in the Geckos, Agamas, and Iguanas, and 

 is probably an organ of taste; in the majority of the other families 

 it is narrow, more or less elongate, often covered with scale-like 

 papilla?, and with a more or less deep incision in front, assuming 

 more and more the function of an organ of touch. It is of extra- 

 ordinary length, worm-like, and terminating in two fine, long points 

 in the Monitors, in which, as in Snakes, it acts as a feeler only. 

 The tongue of the Charnseleons will be noticed subsequently. 



Lizards are spread over the whole world except the very cold 

 regions, and are, like all othei' Reptiles, most numerous, both as 

 regards species and individuals, between the tropics. They are 

 divided into many families, some of which can be alluded to here 

 by name only : 



Families 1. Geckonida. 2. Eublepharida. 3. Uroplatidce. 

 4. Pygopodidae. 5. Agamidce. 6. Iguanida. 7. Xenosaurid<s . 

 8. Zonurida. 9. Anguidce. 10. Anniellidce. 11. Helodermatida. 

 12. Varanidce. 13. Xantusiidee. 14. Teiidce. 15. Amphis- 

 bcenidce. 16. Ltwertida. 17. Gerrhosaurida. 18. Scincidce. 

 19. Anelytropida. 20. Dibamidae. 



The last family, the Chamaleontida, is so distinct from all the 

 others that some herpetologists would remove it from the Lacertilia 

 altogether. 



The majority of Lizards, especially the smaller kinds, are not 

 suitable objects for exhibition in a dry state ; they must be pre- 

 served in spirit ; consequently only a selected series is exhibited 

 in this Gallery. 



