A scale-like covering, which is fixed and immovable, covers the eye of the serpent, as shown in Fig. 4, and gives to it, as Prof. Nicholson vividly expresses it, the "peculiar, stony, unwinking stare" for which they are remarkable, and which, when they are enraged, becomes intensely fierce.
Fig. 10.
Guinea Rock-Snake.
This covering is evidently transparent, as the animal distinguishes forms, but in the cast-off skin it is translucent only. Behind the eye-ball is a lachrymal gland, with a duct which conveys tears to the membranes of the eye. By this means they are kept moist. A conduit connects the eye-cavity with the olfactory opening, and, should the creature shed tears, it would be through that opening, not directly from its eyes.
In common with other animals, serpents have some habits and
