Snakes: Curiosities and Wonders of Serpent Life

by Catherine Cooper Hopley

These are some of the most striking head-appendages; though in the way of pug-nosed ophidians and curious profiles we might give a whole page of illustrations.

In the acrobatic chapter, mention was made of a pair of rudimentary hind limbs in some of the boas. Externally the derm is condensed into ‘claws’ or ‘hooks.’ In form they are merely long, simple appendages, which in the largest boas are about as big as a finger. Claws and hooks they are in the matter of use, being a pair, and they no doubt assist the climbing snakes in grasping.

As a condensed form of the tegument, they are included in this chapter; but as they are truly vestiges of limbs, I will digress a moment to add a word.

Says Darwin on rudimentary and atrophied limbs: ‘The disuse of parts leads to their reduced size: and the result is inherited.’ Some tame little lizards in my possession—our native species—when crawling about their cages scratching the sand or pushing their way among the moss and rubbish, frequently made use of their fore legs only, allowing the hind legs to drag after them, not because the latter were in any way injured, but simply because the lizards could do well enough without them. They were folded back or permitted to lie passively prone against the tail, while the arms and exquisite little hands were sufficient for the work required. They reminded one of Darwin’s words, and though my style of talking to my pets was such as to suit lizard comprehension solely, I did sometimes warn them in plain English. ‘If you don’t give your legs sufficient exercise, they will dwindle away by and by, and your descendants will have no hind legs at all!’

After thus moralizing to the unheeding lacertines, it was with secret gratification that one heard Professor Huxley, in his Lecture on ‘Snakes’ at the London Institution, Dec. 1, 1879, say—as nearly as I can remember—‘In evolution or a gradual change, the lizard found it profitable to lose its legs and become a snake; all modifications are an improvement to the creature, putting it in a better condition.’ In this ‘better condition,’ therefore, does the slow-worm find itself, when it glides noiselessly, and almost without stirring a blade of grass, into its burrow. In other lizards one may sometimes observe that the hind legs are most used in scratching and pushing the earth away. Thus, in the constricting snakes—these descendants of some pre-ophidian lizards—the unused limbs have become obsolete; and the spine, gaining strength with increased action, has at length become to the constrictors their hands, feet, arms, and legs, and endowed with those wondrous capabilities which were described in chap. xii.

To return to the integument. As one of its developments, the hood of the cobra may be included in this chapter, the skin here exhibiting its extensile or expansive construction. It is the longer ribs, about twenty pairs nearest the head (see p. 33), which really do form the hood. These anterior ribs, gradually increasing in length and decreasing again, are not connected with the ventral scales in the same way as those on which the snake progresses, but can be elevated or expanded in the manner familiar to the reader; they then support the extended skin exactly in the way that the ribs of a lined parasol support the fabric; only while the ribs of the parasol spring from a common centre, the ribs of the cobra are attached to its vertebræ, requiring no other agency than the will of the owner. The action of the ribs as expressive of emotion, in several species of snakes, was mentioned page 150. In the ‘hooded’ snakes (naja), it is seen in an extreme degree. Facing you, the angry cobra displays these umbra-like expanded ribs, while the form of the ‘neck’ or vertebral column in the centre is prominently perceptible. When at rest, they all lie flat one over the other, like the ribs of a closed parasol.

In the way of external peculiarities the ‘gular fissure’ may be mentioned. It is merely a slight groove or crease extending from the chin longitudinally under the throat for a few inches or more, according to the size of the snake; a sort of wrinkle (fosse) to admit of expansion during the swallowing of prey.

Externally snakes have no indication of ears; therefore, in the way of integument, there is nothing to describe in their organ of hearing. But the eye covering is a beautiful and wonderful arrangement.

Snakes have no eyelids, and can therefore never close their eyes, a fact which has given rise to a vulgar belief that they never sleep. Their eyes are, however, well developed, particularly in those snakes which live above ground, and are covered with a transparent layer of the epidermis, forming a capsule which is moulted with the cuticle. Physiologists tell us that it is moistened with the lachrymal fluid. Bright and glistening is the serpent’s eye, except previous to desquamation, when, from the new skin forming beneath, it becomes opaque and dull, and the snake is blind for a few days more or less, according to its health at the time. Rymer Jones considers the transparent membrane cast with the slough a real eyelid in a framework of regular scales; Huxley (in the lecture already alluded to) said snakes’ eyelids are as if our two eyelids were joined. In form and appearance this moulted cuticle is singularly clear and shapely: on the outer side, like a miniature watchglass; but within it is a perfect cup, standing up and out from the surrounding scales like a cup in a saucer, the rounded base of which is the transparent skin, as here seen.