500 LACERTILIA 



asyiiimetrical ; the right being reckiced in Amphisbaenidae ; the 

 left ill other cases. 



•Several Autosauri, for instance the Geckos, Psammodromus, 

 and various other Lacertidae have a weak voice. 



The Fat-bodies are mysterious organs which are situated 

 beneath the skin, and extend from the inguinal region forwards 

 along the ventral sides of the belly. They are often of consider- 

 al)le dimensions ; largest in the spring, in both sexes, at the 

 time of propagation. Their colour is greyish-white or yellow, 

 owing to the great accumulation of fat in the meshes of the 

 connective tissue which composes the frame-work of these organs. 

 An artery enters them, breaks up into capillaries, and these com- 

 bine to form an efferent vein. After the time of propagation 

 tliese organs are reduced to grey or reddish flaps, consisting mainly 

 of very vascular connective tissue. G. W. Butler ^ has \vritten a 

 long paper on their morphology. The same author ^ has investi- 

 gated the " sub-divisions of the body-cavity in Lizards, Crocodiles, 

 and Birds," with reference to peritoneal diaphragmatic structures. 



Tiie geographical distribution of the Autosauri teaches 

 few, but important lessons. We have to restrict ourselves to 

 the principal families, leaving out those which are small and 

 have a limited distribution ; also those which, like the few 

 Anelytropidae in Africa and in Mexico, are not natural groups. 



The Geckones, which are probably the oldest of modern 

 Autosauri, are practically cosmopolitan, being absent only in the 

 cold and in the cooler temperate regions. They are common 

 even in Oceanic Islands, for instance in New Zealand and in the 

 Sandwich Islands. Although not at all aquatic, they are 

 particularly fit to be transported accidentally on or in the trunks 

 of floating trees, to which they cling firmly, and they can exist 

 without food for months. I once received a little South 

 American Gecko in perfect health from a grocer, who found it in 

 a well-closed wooden box containing canned meat, two months 

 after delivery of the box in Cambridge. 



The Scincidae, likewise' an old family, are equally cosmopolitan, 

 but although many exist in the islands of the Pacific they do 

 not occur in New Zealand. Many of the genera have a very 

 wide distribution ; for instance, Lygosoma, with its one hundred 

 and sixty or more species, occurs in the Australian and Palaeo- 

 1 P.Z.S. 1889, p. 602. " P.Z.S. 1889, p. 452. 



