THE LIMBS OF LIZARDS 137 



California, in which there are still fore-limbs with 

 four clawed digits. This family (Amphisbsenidse) in- 

 cludes a number of species which are burrowing in 

 habit and limbless ; Chirotes being the only species 

 with limbs. In most cases the pectoral and pelvic 

 girdles are to be found in a vestigial condition ; but in 

 one family (Dibamidse) not merely the Hmbs, but the 

 limb girdles also are absent, though in the males there 

 are flaps which seem to indicate limbs. The family 

 to which the slow-worm belongs (Anguidae) seems to 

 be in a state of change, there being a general tendency 

 to reduce and lose the limbs, which " may be more or 

 less developed, or entirely absent externally, in which 

 case, how^ever, the rudiments of the pectoral and 

 pelvic arches are always present " (British Museum 

 Catalogue, G. A. Boulenger). Another member of the 

 slow- worm family (Ophisaurus apus) possesses external 

 rudiments of hind-limbs. This last species is of 

 interest because the shape, arrangement, and number 

 of the head shields are extremely similar to those of 

 the slow-worm. It is known as the glass snake, and 

 is found in South-Eastern Europe, South-Western Asia, 

 and North Africa, growing to a length of 3 feet. 

 Finally, in this connection may be mentioned the 

 genus Chamcesaura, a South African genus, with three 

 species which exhibit a curiously progressive diminu- 

 tion in the limbs which may be thus summarised : — 



1. C. cenea. — Both pairs of limbs present, penta- 

 dactyle. 



