138 BRITISH LIZARDS 



2. G. anguiim. — Both pairs of limbs present, reduced 

 to stumps (styliform and undivided). 



3. C. macrolepis. — Fore-limbs absent ; hind-limbs 

 styliform, undivided. 



A more gradual and complete reduction is seen if 

 the whole of the genera in the slow-worm family be 

 compared. Thus : — 



Synopsis of the Genera in the Anguid^. 



1. Gerrhonotus. — Limbs four, pentadactyle. 



2. Ophisaurus. — Limbs absent, or hind pair rudi- 

 mentary externally. 



3. Diploglossus. — Limbs four, pentadactyle. 



4. Satcresia. — Limbs four, tetradactyle. 



5. Panolopus. — Limbs four, monodactyle or di- 

 dactyle. 



6. OpJiiodes. — External rudiments of the hind-limbs 

 only. 



7. Anguis. — No trace of limbs externally. 



Here we have in the one family a number of genera 

 exhibiting a series of variations from the four-limbed 

 five-fingered type to the highly specialised serpentiform 

 creature without any external limbs at all, as in the 

 slow-worm. It is the existence of so many inter- 

 mediate conditions of organs that proves animals to 

 be connected by almost every possible structural 

 modification, and which makes it impossible to believe 

 that species could have arisen except by a gradual 

 transition of forms from the generalised type to the 



