XII 



ANATOMICAL STRUCTURE 



569 



granules. The eyes are very remarkable. The eyeballs them- 

 selves are large, but the eyelids are united into one fold with 

 a small central opening. However, when the Chameleon is asleep 

 the margins of this opening sometimes become more slit-like. 

 The right and left eye can be, and are incessantly, moved 

 separately from each 

 other, and the creature 

 squints terribly. Each 

 eyeball, together with 

 the pin-hole eyelid, is 

 rolled up and down, 

 backwards and forwards, 

 independently of the 

 other eye. This is a 

 unique feature, but it 

 also occurs in people 

 who squint badly. The 

 question " What, and 

 how, do these creatures 

 see ? " is therefore quite 

 idle, especially since in 

 reptiles binocular vision 

 does not exist at all and, 

 consequently, cannot be 

 disturbed by squinting. 



The tongue has 

 attained an extraordin- 

 ary development. The 



tongue proper (Fig. 152) FlG . 149. _A, Dorsal, B, ventral, and C, lateral view 

 IS club - shaped and is ^ * ne skull of Chamaeleon vulgaris. x 1. Cond, 



occipital condyle ; EP, ectopterygoid ; Jug, jugal ; 



Covered With a Sticky Lac, lacrymal ; Pal, palatine ; Par, parietal ; Prf, 

 Secretion The base or prefrontal ; Pt.f, postfrontal ; Ptg, pterygoid ; 



Q, quadrate ; Sq, squamosal ; Vo, vomer. 



root of the tongue is very 



narrow, composed of extremely elastic fibres, and is supported by 

 a much -elongated copular piece of the hyoid. The elastic part 

 of the tongue is, so to speak, telescoped over the style-shaped 

 copula, and the whole apparatus is kept in a contracted state like 

 a spring in a tube. 



A pair of wide, very elastic blood-vessels and special elastic 

 bands extend from the base into the thick end of the tongue. 



