Dr. Cantor had previously made many experiments on various dumb creatures in order to ascertain the virulence of the poison of these hitherto unstudied reptiles. He found that a fowl died in violent spasms eight minutes after a bite; and a second fowl, bitten directly afterwards by the same snake, with its half-exhausted venom, in ten minutes. Fish died in ten minutes; a tortoise in twenty-eight minutes, from the bite of another species; and a harmless snake was paralyzed within half an hour.
Among the fresh-water snakes, Dr. Günther tells us of one, Hydrinus, which is semi-pelagic, and which indulges in little excursions down the rivers to exchange greetings with his marine relatives, some of whom, on their part, occasionally go a certain distance up the rivers. Again, among the sea snakes is one who rambles for change of air or diversity of diet over the fields and far away. In him, Dr. Günther describes one of those many transitions found in every class and order throughout nature. Platurus is his name; he has the ventral scales of land snakes to enable him to wander over the salt water marshes which he loves. His nostrils are on the side of his head instead of on the top, and his head shields differ from those of all his relatives. His venom fangs are small, and his tail is not prehensile, presenting the united characters of fresh and salt water and land snakes. Thus we have links between sea and land snakes, between fresh water and salt, and between these latter and fishes, for in many instances the affinities are so close that naturalists have doubted in which class to place them. When that remarkable animal, the Lepidosiren, which Darwin calls a living fossil, was first brought from Africa some thirty years ago, it was found to present so many characteristics in common with both reptiles and fishes, that it was for some time a mooted question in which class to place it. In appearance it more resembles the former, with its four curious filamentary limbs, which Owen considers ‘the beginnings of organs which attain full functional development in the higher vertebrates.’ The same high authority has decided that the only character which absolutely distinguishes fishes from reptiles, so closely are some of them allied, is whether or not there is an open passage from the nostrils to the mouth; and the ‘Lepidosiren’ is now known as ‘the mud-fish of the Gambia,’ the ichthyic characters predominating.
Sea snakes were not unknown to the ancients. Aristotle mentions them (Taylor’s Translation, 1812, Book ii. vol. 6), ‘Of sanguineous animals, however, there remains the genus of serpents. But they partake of the nature both of terrestrial and aquatic animals. For most of them are terrestrial, and not a few are aquatic, and which live in potable water. There are also marine serpents similar in form to the terrestrial genus, except that their head more resembles that of a conger. There are, however, many genera of marine serpents, and they are an all-various colour; but they are not generated in very deep places.’
These latter words suggest what has not been mentioned as a positive fact, while yet in part it is corroborated by Cantor, who tells us that the young sea snakes feed on soft-shelled molluscs; we may argue, therefore, that the mother snakes come into shallow water to give birth to their young, where small fish and suitable food may abound. Aristotle was evidently aware of the distinctions between fresh and salt water snakes, and gives us the former as frequenting rivers (‘potable waters’).
The Greek mariners who frequented the tropical seas knew of the poisonous snakes with wholesome dread. Sir Emerson Tennant tells us that the fishermen on the west coast of Ceylon are still in perpetual fear of them. They say there are some with the head hooded like the cobra, that coil themselves up like serpents on land, not only biting with their teeth, but ‘crushing their prey in their coils.’
The ‘hood’ part of the story is not borne out by any scientific writer; and as for the ‘crushing in coils,’ the sailors may possibly mistake the prehensile actions of holding on—even to a large fish—possibly for the action of crushing in the way of constricting. In self-protection, or for safety, venomous serpents do entwine themselves pretty tightly round an object sometimes. An instance of this was just now given. But constricting for the purpose of killing is happily confined to the non-venomous families. It would indeed be terrible if the ‘giants of the waters’ could both constrict and bite with poison fang; and of this a word or two will be said in the following chapter. Admittedly but little has been accurately ascertained about the marine serpents in comparison with the terrestrial ones. And there really may be species hitherto unobserved. The great sea serpent question is not yet satisfactorily settled; and among the lesser kind, the true pelagians, varieties are frequently occurring. Krefft describes one in the Australian Museum which, not being like any other that he had seen, he sets down as a new type. Forty-eight distinct species were described by Cantor. The whole family comprises seven genera, four of which belong to the Indian Ocean.
