Weeks of wondering suspense passed by. Then everybody went ‘out of town.’ On meeting Dr. Günther one day at the British Museum, I told him what I had seen. ‘The teeth or the jaw moves?’ he asked catechetically. That I could not explain, as it was precisely what one wished to ascertain. ‘You must dissect that snake,’ he said, adding that he had had no time to examine it yet. All this was duly reported to my Brazilian correspondent, who with a generous impulse promised to send me ‘the very first Xenodon’ he got. Alas! as I told him, it was useless to give it to me, who could neither kill nor cut up snakes. He did not inform me whether he, also, had observed any mobility in the ‘fangs;’ so I could not yet flatter myself that I had ‘added to science’ in any way. Professor Halford, when in England, had dissected the head of the dead specimen at the Zoological Gardens (the supposed Jarraracca) for poison glands, but of course found none; and I trusted to some scientific friend ‘happening by’ who would further examine its maxillary bone and report to me; but ophiological anatomists do not present themselves every day. Dr. Stradling was absent; so unless other enthusiasts proceed to an examination before this page meets the public eye, there will still remain these ‘strange-toothed’ maxillaries inviting dissection.
Dr. Stradling, however, after a while informed me that he had not observed the mobility of the fangs, nor had he seen any mention of such anywhere excepting in my paper to Land and Water (July 9, 1881). He thought those pseudo-fangs ‘of considerable importance in bearing on the experiments that were then being carried on in Brazil with permanganate of potash, and particularly should a non-ophiologist be the experimenter.’ A snake is brought as a ‘Jararaca,’ a name applied by the authorities to one of the very deadly viperine snakes. This snake—the so-called ‘Jararaca’—bears an evil character. It has also very suspicious-looking ‘fangs.’ It bites an animal which is put under treatment, and though requiring no treatment whatever, a supposed ‘antidote’ might get all the credit of a ‘cure.’ He did not for a moment infer that such had been the case in Brazil with those scientific experimentalists, but only what might be in consequence of the confusion in names. And the correspondence on this subject that appeared in the papers during the latter part of October 1881 certainly did betray some confusion between the various Jararacas and Jararacucus that had inflicted bites.
Dr. Stradling had also looked in the mouth of the dead specimen of Xenodon rhabdocephalus, and he informed me that one of the ‘fangs’ came out in his hand. ‘It did not break off,’ he wrote; ‘and its articulation with the bone, if any, must be loose and ligamentous.’ I must not presume to offer any opinion about its ‘articulation,’ except that its being ‘loose’ might be only in consequence of a new tooth pushing it out, or that it was about to fall out of itself. My readers will unite in thanking Dr. Stradling for considerately forwarding me this ‘fang,’ which so conveniently detached itself in time to be added to the rest of the illustrations, fig. e, presented on p. 360. It will be observed that it is a stouter and less symmetrical tooth than the true fangs; but it was very large in proportion to the simple teeth in the same jaw and on the palate, and which are not bigger than the palate teeth seen behind the recumbent fangs of Daboia, p. 349.
Of these true Xenodons there are eight species; but the strange-toothed group includes Tomodon, Heterodon, Simotes, Liophis, and several others that have large posterior teeth, some of which are grooved, others not, but all without a poison gland.
Searching page after page about Xenodon, something one day suddenly caught my eye that had hitherto escaped notice. In his Odontography, Owen, describing the South African snakes Bucephali, says: ‘Their long grooved fangs are firmly fixed to the maxillary bone, or are slightly moveable according to their period of growth; they are concealed by a sheath of thick, soft gum, containing loose, recumbent, grooved teeth ready to succeed those in place.’
‘So, then, a mobile tooth was already known to science.’ Of Bucephali viridis, Dr. Andrew Smith describes the ‘posterior or mobile and grooved teeth of the maxilla.’ He says: ‘Some are placed for immediate use, the rest are recumbent between those and the inner portion of the spongy sheath which envelops them; anterior teeth fixed.’ He considered these back teeth not poisonous, but only for holding or preventing the escape of food. ‘They may convey an acrid saliva.’ Still we are not informed how the teeth move.[113]
These snakes—the Bucephali—like the far-famed horse of Alexander the Great, owe their name to their large, ox-shaped head. They are the ‘Boomslange’ or tree snake of the Dutch settlers, and are by some ophiologists included among the Dendrophidæ, or true tree snakes, as they live in trees; but Dr. Andrew Smith considers that their teeth sufficiently separate them from these.
That there is something exceedingly interesting to study out in the Xenodon family cannot be doubted. ‘The transition begun in the Bucephali,’ says Owen,[114] ‘is completed in the poisonous serpents,’ but where the virulent character of the saliva begins it is hard to say.
Despairing of any distinct comprehension of a jaw-bone which permits of moveable back teeth, the last resource was to hunt up a skeleton. At the Museum of the Royal College of Surgeons none was to be found; but through the kindness of the officials at the British Museum, one was at length unearthed from the subterranean labyrinths of untold treasures there. It was the skull of X. gigas, the largest of the family, and a splendid specimen for examination. There were two large posterior fangs on each side. On one side were two or three more large reserve fangs—a cluster of them. All were recumbent. They were all much larger than that of X. rhabdocephalus, those in reserve varying in size relatively to their development and position. In this specimen there were also two double rows of palate teeth, and an abundant but most disorderly row of simple teeth in the lower jaw, with some reserve ones packed closely on the inner side below the row in use. They exactly illustrated the words of Nicholson and others, ‘the crop of young teeth everywhere working their way into the intervals of the old ones.’
In the skulls of Liophis meremii and Liophis cobella, of which Dr. Wucherer says, ‘Dentition similar to Xenodon,’ the former had teeth gradually increasing a trifle posteriorly, but nothing like fangs. L. cobella had a very long jaw of fifteen or sixteen teeth, but no fangs.