in length within a space no larger than the hollow of your hand.  They appear to be always watchful; for at the instant you discover one, the quick playing of the long, black, forked tongue will show you that you too are observed.  On perceiving the slightest sign of your intention to disturb it, the snake will dart upwards through the branches and over the leaves which scarcely appear to bend beneath the weight.  A moment more, and you have lost sight of it.  Whenever I return to Europe, you may be sure that in my hot-house those harmless, lovely creatures shall not be missing.”

[Footnote 1:  Dr. WUCHERER of Bahia.]

[Illustration:  TREE SNAKE.  Passerita fusca.]

Ceylon has several species of Tree-snakes, and one of the most common is the green Passerita, easily recognized from its bright colour and from the pointed moveable appendage, into which the snout is prolonged.  The snakes of this genus being active chiefly during the night, the pupil of the eye is linear and horizontal.  They never willingly descend from trees, but prey there upon nocturnal Saurians, geckoes, small birds and their young; and they are perfectly harmless, although they often try to bite.  It is strange that none of the numerous specimens which it has been attempted to bring to Europe have ever fed in captivity; whilst in South America they take their food freely in confinement, provided that some green plants are placed in their cage.

In Ceylon I have never seen any specimen of a larger size than three feet; whilst they are known to attain to more than five on the Indian Continent.

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.