From Fayrer’s Thanatophidia. The four larger dots represent fangs.
Fayrer divides the poisonous snakes of India, again, into four families, viz. Elapidæ and Hydrophidæ, with fixed fangs; and Viperidæ and Crotalidæ, with mobile fangs.
But without so many perplexing distinctions, I hope to be able to interest the reader in that wonderful piece of mechanism, the poison fang, and by the aid of the authorities to represent it in simple language.
We have long been accustomed to read that a serpent’s fang is a ‘perforated tooth’ or a ‘hollow tube,’ as if a miniature tusk had a hole bored through its entire length, the poison entering at the root and flowing out again at the point. This is not strictly the case. Fangs in their construction are not absolutely ‘hollow,’ with ivory on the outside and pulp on the inside, but are as if you had flattened out an ivory tusk and folded or wrapped it over again, so as to form a pointed tube. It would then have dentine both on the outer and inner surface. This involution may be compared with that seen in a long narrow leaf, in which the larva of an insect has enwrapped itself. The various degrees of involution are extremely close, as also would be the forms of leaves and the extent of curling which each caterpillar had effected. Some fangs are folded so as to leave the—join, we will call it, easily perceptible. Others leave a groove more or less evident; while in others the fold is so complete as to have disappeared entirely. Schlegel, in describing the insensible passage from solid teeth to fangs, affirms that traces of the groove are always perceptible: ‘On découvre toujours les traces de la fente qui réunit les deux orifices pour le venin.’[94]
Two fangs magnified, showing
the slit more or less complete.
c, a section. From Fayrer’s
Thanatophidia.
In a mixed collection of thirty odd fangs of various snakes lent to me by Holland, the keeper, for examination, and sent all together in a little box, there were few in which I could not discern the join. The keeper was not sure to which snakes each belonged, excepting one or two of the largest, which were those of a puff adder. Those of the larger Crotalidæ I could identify by the peculiar curve. In a functional fang of the ‘bushmaster’ (Lachesis mutus), which I myself took from its jaw, there is a well-defined line, like a crack, the whole way down, from the base to the slit; in a rattlesnake fang, also in my possession, there is a faint appearance of this line or join; and in a young Crotalus fang it is still there,—only a faint crack, such as you would contemplate with alarm in your egg-shell china, still there it is.
It is scarcely necessary to explain that fangs differ in size in different families, as well as proportionately to the size of the possessor. In sea snakes they are not much larger than the simple teeth behind them. In the Cobra they are larger than in the Bungarus; in the viper they attain their largest size.