OVOVIVIPARITY 
it is not so frequently seen as the more active common 
lizard Lacerta agilis, on account of its retiring habits. 
Unfortunately for itself the slow-worm does not dislike, 
indeed it seems to prefer, the neighbourhood of human 
habitations ; this is unfortunate, for the animal has 
succeeded in gaining a most terrific reputation for 
poisonous properties, of which it has not the slightest 
hint. It has thus suffered much persecution by hob- 
nailed boots. It is true that the slow-worm will bite 
at times, especially during the breeding season, which 
seems to be productive of irascibility in the animal 
world generally. But its tiny teeth will not scratch, 
let alone bite, the human skin to any purpose. It has 
been pointed out, however, that this reptile has some 
of its teeth grooved. Now that is a character of the 
only known poisonous lizard Heloderma, and of certain 
snakes known as venomous colubrines. But there is no 
developed salivary gland in association with these 
grooved fangs, which are, however, sufficient to retain 
a hold of slugs, which the slow-worm particularly affects 
as food. Anguis fragilts occurs nearly all over Europe, 
avoiding the colder northern regions ; like most other 
reptiles it is not to be found in Ireland. It brings forth 
its young alive like many lizards, but this process 
must not be confounded with the mammalian method 
of gestation. For in the snake the eggs are merely 
retained in the oviduct until they are hatched; there 
is not any connexion by growth with the parent as 
in the mammalian foetus. The family to which Angus 
fragilis belongs, the anguide, contains a number of 
other forms of which some are legless, and others possess 
the normal complement of three appendages. The 
large grass snake of Russia and Morocco, often to be 
seen at the Zoo, grows to three feet or so in length and 
is much like an enlarged edition of the slow-worm ; 
but it has, which the slow-worm has not, a deep groove 
233 
