After reading this, I noticed the varieties of colour in all the ‘forked tongues’ that exhibited themselves at the Zoological Gardens. Black or very dark tongues, I think, predominate; and next to black, brownish or olive tints, resembling those of the snake itself. But not as a rule; for some very light snakes have dark tongues, and the converse. In two small green tree snakes of distinct genera, one had a pale pink or flesh-coloured tongue, and the other a black one. Some tongues are almost white, while a few are red. There seems to be as much caprice as in the colour of the human hair and eyes; and as physiologists have traced some sort of connection or relationship with complexions and constitutions in these, so ophiologists may, after a time, discover a similar relation or sympathy between the colour of a snake’s tongue and its integument or eyes. At present, I have observed only so far as that two entirely black and two entirely green snakes may present four distinct colours as regards their four tongues, and that many tints of brown, black, and pink may be seen in the tongues of as many snakes. [Illustration] [Illustration] CHAPTER VIII. _THE GLOTTIS._ ONE Friday in august 1873, while watching a large python, at the Zoological Gardens, swallowing a duck which it had just killed, I was struck by a singular something projecting or hanging from the side of the snake’s mouth. It looked like a kind of tube or pipe, about one inch and a half or two inches of which were visible. The python had rather an awkward hold of the duck, having begun at the breast with the neck doubled back, the head forming some temporary impediment to the progress of the jaws upon the prey. So the strange protuberance gave one a ‘sort of turn,’ and a shudder. It looked as if it might be some part of the crushed bird, and then again it had the appearance of some internal arrangement; and another shudder crept over one as the idea suggested itself that the poor snake had ruptured its throat in some way. What _could_ this queer thing be, hanging on one side, as you see the tongue of a horse or dog sometimes lolling sideways over its lower jaw? While intently pondering and observing this strange tube-like object, in size somewhat as big as the edge of a thimble, I saw the end of it moving of itself, an orifice contracting and closing tight, by the loose skin puckering up, so to speak. Presently it opened, and by and by again closed tight, as you see the breathing orifice of the octopus contract and expand, open and close, at regular intervals, only in the present case the intervals were not regular. This strange tube, then, had life and volition in it! What could it be?