44 REPTILES AND BIRDS. 
and Fresh-water Colubrines (JVatricine) ; and he remarks that “ they 
are found in every part of the temperate and tropical regions, but 
are only scantily represented in Australia and in the islands of the 
Pacific. ‘The species are so numerous, and show such a gradual 
passage between extreme forms, that, although genera can be easily 
characterised, it is almost impossible to distinguish wider groups by 
definite characters.” Among them the Coronelling approximate to the 
immediately preceding families, and, like them, live on the ground, 
and are not generally of brilliant colouring, though a few species 
which frequent grassy plains are of a bright green colour., The 
Colubrine “form, as it were,” writes Dr. Gunther, “the nucleus 
of the whole sub-order of innocuous Snakes ; they are typical forms, 
not characterised by the excessive development of some particular 
organ, but by the fairness of the proportions of all parts. Yet some 
of them have a more slender body than others which always live on 
the ground; they are land Snakes, but swim-well when driven into 
the water, or climb when in search of food. ‘They are of moderate 
or rather large size.” In the Dryadine the form is elongate and 
somewhat compressed, indicating their climbing propensities ; they 
have the body not so excessively slender as in the true Tree 
Snakes, to which they lead off. They are much more numerous in 
the New World than in the Old, and their ground-colour is very 
commonly green. The /Vatricine are generally not very elongate or 
compressed, and most of them have keeled scales. They freely enter 
the water in pursuit of their food, which consists chiefly of frogs and 
fishes. All the Snakes of the preceding three sub-families overpower 
their prey by throwing some coils of the body round it, and commence 
to swallow the victim after it has been smothered. The /Vatricine 
swallow their prey immediately after they have seized it. 
Of the sub-family Coronelling, one species of the typical genus 
Coronella is widely diffused over Europe, and has only of late years 
been recognised as an inhabitant of the British Islands, the Corone//a 
austriaca. Another, C. g¢vondica, occurs in Italy. Others are found 
in Africa, America, and Australia. The C. austriaca has somewhat 
the appearance of the Common Adder, for which it is often mistaken ; 
but it 1s non-venomous, though rather fierce, biting and holding on 
to whatever is placed in its way. As it occurs in Malta (where no 
venomous species is known to exist), it is doubtless the Viper which 
seized the apostle Paul. Several other genera are recognised. 
Of the Colubrine Rhinechis scalaris, Coluber esculapit, C. quad- 
rilineatus, Elaphis quater-radiatus, and three species of Zaments 
inhabit Europe ; in North America there are to be found five species 
