DIVISIONS OF REPTILIA. 269 
Blind-worm (Angus fragilis) of our own country, exhibit no 
external indications of limbs, and would therefore be generally 
regarded as Snakes. ‘These snake-like Lizards, however, can 
be distinguished from the true Ophidians by the consolidation 
of the bones of the head and jaws, and by the fact that the eyes 
are generally provided with movable eyelids. Dissection also 
shows that the shoulder-girdle (or scapular arch) is always 
present in a rudimentary condition. 
Few Lizards are natives of Britain ; the only forms which can. 
be said to be at all abundant being the Blind-worm or Slow- 
worm and the Sand-lizard (Lacerta agilis). Of the snake-like 
Fig. 145.—Blind-worm (Anguis fragilis). (After Bell.) 
Lizards, a good example is to be found in the common Blind- 
worm or Slow-worm of Europe. It is completely serpentiform, 
without any external indications of limbs (fig. 145), and it is 
quite harmless. It is remarkable for the fact that, when 
alarmed, it stiffens its muscles to such an extent that the tail 
can readily be broken off, as if it were brittle. This same 
brittleness exists in the Glass-snake (Ophisaurus ventralis) of 
the Southern States, in which also there are nolimbs. In other 
allied genera, there may be fore-feet alone, or hind-feet may be 
present, or all four limbs exist in a more or less rudimentary 
