200 
SNAKES. 
Water-Snakes. 
The large group of water-snakes bring us to the second and 
by far the largest subfamily of the solid-toothed colubrines, which 
is known as the Colubrince, and is distinguished from the preceding group by the 
supratemporal bone not being produced over the region above the socket of the 
eye; while the scales are usually overlapping, and teeth are present throughout 
the entire length of the upper and lower jaws. The water-snakes belong to a 
large assemblage of genera of the subfamily characterised by the circumstance 
that in the skeleton of the backbone inferior projections or spines are present 
throughout its length, the vertebrae in the hinder region of the body having 
these spines represented by a more or less well-developed crest or tubercle. 
From their allies, the water-snakes are distinguished by having the hinder upper 
teeth larger than those in front, the equality in the size of the lower teeth, the 
rather large size of the eye, in which the pupil is round, the presence of a pair 
of internasal shields between the nostrils, the regular longitudinal series formed 
by the scales throughout the body, and by the teeth in each hinder upper jaw¬ 
bone varying in number from eighteen to forty, and forming a continuous series. 
Represented by over forty species, the water-snakes have an almost cosmo¬ 
politan distribution, although they are unknown in South America, while in 
Africa south of the Sahara they are less abundant than in other regions, and in 
Australia they occur only in the northern districts. Dr. Gunther writes that the 
typical water-snakes “ are easily recognised by their stoutish cylindrical body, 
keeled scales, flat head covered with regular shields, wide cleft of the mouth, and 
numerous teeth, the strongest of which are at the hinder end of the maxillary 
bone. They frequent the neighbourhood of fresh water, and feed on aquatic 
animals—frogs, toads, and fishes. They do not overpower or kill their prey by 
throwing a coil of the body round it, but, having seized it, they at once commence 
to swallow it. They are excellent swimmers, but more frequently live near water 
than in it, in agreement with which habit, the position of their nostrils is not on 
the upper surface of the head, as in the true freshwater snakes, but on the side.” 
The best known and at the same time the typical representative 
of the group is the common ringed snake (Tropidonotus natrix), 
inhabiting Europe, Algeria, and West and Central Asia, and attaining a maximum 
length of 61 feet. Belonging to a group of the genus in which the number of 
teeth in the hinder upper jawbone does not exceed thirty, this snake has a single 
anterior temporal shield on the head, usually seven upper labial shields, of which 
the third and fourth enter the aperture of the eye, and from one hundred and fifty- 
seven to one hundred and ninety shields on the lower surface of the body. The 
eye is of moderate size, and most of the scales are strongly keeled. The colour 
is usually grey, olive, or brown above, with spots or narrow transverse bands; the 
labial shields being white or yellowish, with their dividing lines black; while 
the under-parts are mottled black-and-white or grey. There are, however, several 
variations as regards the coloration of the neck. In the ordinary variety, for 
instance, there is a white, yellow, or orange collar, usually divided in the middle, 
behind which is a broad black collar; the latter being sometimes alone present. 
In another variety, mostly from the south of Europe, the collar is altogether 
wanting, or reduced to a small black patch on each side of the nape; while in the 
Ringed Snake. 
