506 LACERTILIA GECKONES CHAP. 



cylindrical and tapering to a point, it is leaf-like in Gymno- 

 dactylus platurus of Australia ; provided with many lobes, and 

 used as a parachute in the Malay Ptycliozoon. In Nephrurus 

 asper of Eastern Australia the tail is quite short, much shorter 

 than the limbs, much swollen at the base, and very thin towards the 

 end, which carries a round knob. The tail of all Geckos is very 

 brittle and can be quickly regenerated, except the long rat-like tail 

 of the Persian Agamura. In many other desert-forms the tail is 

 long, slender, and laterally compressed, acting in such cases like 

 that of desert-forms among the Lizards. 



Many Geckos have a voice, mostly rather feeble, and sounding 

 like a soft " click " or " chick " produced by our tongue. Kepe- 

 tition of this sound resembles in some species the word " gecko." 

 They lay eggs, rather globular, or but slightly oval, hard-shelled, 

 and white, mostly two in number. Naultinus elegans of New 

 Zealand is said to be viviparous. The males are generally larger 

 than the females, and they are further distinguished by the 

 possession of femoral or pre-anal pores. 



All Geckos feed upon animals, chiefly upon insects, but the 

 larger forms take anything they can master. With few excep- 

 tions they are nocturnal, which, however, does not prevent them 

 from occasionally baking themselves in the sun. They are 

 capable of changing colour, but since their ground-colour is 

 almost universally grey, yellow, or brown, the range of the colour- 

 changes is restricted to the adoption of darker or lighter hues. 

 The skin is shed in flakes and eaten. 



Geckos are absolutely harmless ; they cannot even inflict 

 painful bites. However, in many countries they are feared as 

 much or even more than the most poisonous snakes. In the 

 south of Spain and Portugal, for instance, where Geckos are 

 plentiful in and outside the houses, and are consequently objects 

 of daily observation, the " osga " is considered a dreadfully 

 poisonous creature. They become very tame, or rather confiding 

 in their regular habits, provided they are not molested. If 

 caught and they have many enemies among other lizards and 

 snakes the only safety of these defenceless and mostly small 

 creatures lies in their tail, which, being extremely brittle, is left 

 in the claws or jaws of the pursuer. The remaining stump soon 

 produces a new tail, in shape and size like the old one, but with 

 a different and simpler scaling. I knew of several specimens of 



