The inference is obvious, that the green coloration of the majority of tree-snakes has more or less connection with their habits and mode of life. Indeed, whenever a green-coloured snake is observed, it may at once be pronounced, if slender or provided with a prehensile tail, to be of the kind which passes its life on trees; but if it be short-bodied then it lives on the prairies. There are nevertheless tree-snakes which have a very different coloration; and one of the most remarkable species is the _Passerita fusca_ or _Dryinus fuscus_, of which a figure is annexed. It closely resembles the green Passerita in form, so that naturalists have considered it to be a mere variety. It is entirely of a shining brown, shot with purple, and the yellow longitudinal stripe which runs along the side of the belly of the green species, is absent in this one. It is much more rare than the green one, and does not appear to be found in Hindostan: no intermediate forms have been observed in Ceylon. _Water-Snakes._--The fresh-water snakes, of which several species[1] inhabit the still waters and pools, are all harmless in Ceylon. A gentleman, who found near a river an agglutinated cluster of the eggs of one variety (_Tropidophis schistosus_), placed them under a glass shade on his drawing-room table, where one by one the young reptiles emerged from the shell to the number of twenty. [Footnote 1: Chersydrus granulatus, _Merr_.; Cerberus cinereus. _Daud._; Tropidophis schistosus, _Daud._] The _sea-snakes_ of the Indian tropics did not escape the notice of the early Greek mariners who navigated those seas; and amongst the facts collected by them, Ælian has briefly recorded that the Indian Ocean produces serpents _with flattened tails_[1], whose bite, he adds, is to be dreaded less for its venom than the laceration of its teeth. The first statement is accurate, but the latter is incorrect, as there is an all but unanimous concurrence of opinion that every species of this family of serpents is more or less poisonous. The compression of the tail noticed by Ælian is one of the principal characteristics of these reptiles, as their motion through the water is mainly effected by its aid, coupled with the undulating movement of the rest of the body. Their scales, instead of being imbricated like those of land-snakes, form hexagons; and those on the belly, instead of being scutate and enlarged, are nearly of the same size and form as on other parts of the body. [Footnote 1: "[Greek: Plateis tas ouras]." ÆLIAN, L. xvi. c. 8. Ælian speaks elsewhere of fresh-water snakes. His remark on the compression of the tail shows that his informants were aware of this speciality in those that inhabit the sea.]