Chapter XXII: The Xenodons

_AND MY ‘DISCOVERY.’_

THOUGH there are only about eight species that have a legitimate right to this patronymic, there are—as my readers have seen in chap. xix.—great numbers of ‘strange-toothed’ snakes that have a zoological, or rather a dentitional right to it. The present chapter, however, will comprise only a few of those most nearly allied to the recognised _Xenodons_, which with _Heterodon_ must occupy some pages.

The _Xenodons_ have an especial interest, not only on account of their remarkable dentition, but their vernacular names, which in Brazil, where these snakes are common, have led to much and frequent confusion. This can be remedied only after considerable lapse of time, for the confusion has unfortunately been disseminated in print, and the vernaculars, confused by local prejudices, still obtain. The incident of my own first acquaintance with a _Xenodon_ will in part explain the kind of puzzle which prevails; and a little personal gossip about this may, I trust, be tolerated.

A snake mentioned by a number of writers and travellers as the _Jararaca_ had plagued me long and terribly, from the contradictory accounts of it. What _is_ this Jararaca? And is it the same as the _Iarraracca_ or the _Ibiracua_ or the _Iraracuassa_ or the _Shiraraca_, or several other nearly similar names which appear in books about Brazil. Had one gone straight to Gray or Dumeril, the recognised and scientific name for it could have been ascertained at once; but we do not so readily find out which _are_ the right books to pounce upon, nor had I in those days learnt the necessity of trusting to scientific works only for the unravelling of travellers’ tales; but I hunted in dictionaries and encyclopedias and travels and those old authors again, but with no better success.

In Wallace’s _Travels in the Amazon_ we read: ‘Hanging up under the eaves of our shed was a dried head of a snake which had been killed a short time before. It was a _Jaráraca_, a species of _Craspedocephalus_, and must have been of formidable size, for its poison fangs, four in number, were nearly an inch long.... The bite of such would be certain death.’

With this picture of a large Brazilian serpent, drawn by such an authority as Wallace, one read in Ogilvy’s dictionary: ‘_Jararaca_. A species of serpent in America, seldom exceeding eighteen inches in length; having prominent veins on the head, and of a dusky, brownish colour, variegated with red and black spots.’

Then Webster—evidently from the same source: ‘A species of serpent in America,’—word for word the same as far as the black spots—‘very poisonous. Native name in Surinam.’ And in a newer edition, Webster, in addition, gives its scientific name, _Bothrops Jararaca_; and that it is ‘a native to (_sic_) Brazil.’

‘Oh! if a _Bothrops_, then it is one of the _Crotalidæ_,’ was the decision arrived at. Kingsley, in his _At Last_, mentions a ‘mangrove snake, much dreaded by being so like the deadly Cascobel, viz. _Trigonocephalus jararaca_.’ Thus with our puzzle we combine a _Bothrops_ with the ‘pit;’ a _Trigonocephalus_ with the worst of the viperine heads; and according to Wallace, a _Craspedocephalus_, which, at a guess, must be that it has something rough about the head to entitle it to this specific.

Few of the encyclopedias described it individually, or threw more light upon it. Worcester’s dictionary states that the Jararaca is ‘a species of venomous American serpent seldom exceeding eighteen inches;’ and gives Wright as an authority. Spix and Martin[110] in their list of venomous snakes describe _Jararacucu_, called also _Shiraraca_, as a _Bothrops_; and also a _Jararaca mirim_, a small one. Marcgravius[111] figures a _Iararaca_, a small snake of a bright red with black spots.

And now for our old friend the Pilgrim Purchas. ‘Of snakes that have Poison, _Iararaca_ is a Name that comprehendeth foure kinds. The first is the greatest _J_. There are other smaller _Jararacas_, about half a Yard long. They have certaine Veines in their Head like the Vipers.’

Have those ‘prominent veins anything to do with its name _Craspedocephalus_’? But how about its being only eighteen inches? This was the pursuit of snakes under difficulties, the clearing away of which was accomplished only by slow degrees, as one book after another offered new contradictions with still other varieties of spelling. Without doubt this perplexing reptile was viperine, rough, angular-headed, crotaline, and probably hideous; but as for colouring there were many doubts about that.

After several years’ familiarity with the _name_ of this puzzling ‘Jararaca,’ and curiosity increasing at a corresponding ratio, the reader can imagine the effect produced by unexpectedly seeing at the London Zoological Gardens one day in September 1880 a new label to one of the cages in the Ophidarium thus inscribed, ‘CRASPEDOCEPHALUS BRAZILIENSIS. THE JARRARACCA. Presented by Dr. Stradling.’

A live Jararaca at last! Now we shall know all about it.

But how is this? The serpent before me was not a viper, not rough-headed, not a _Bothrops_, because it had only one pair of nostrils. It had smooth, polished scales, large, beautiful, round eyes, with no ‘red spots’ and not a spice of venom or of viperishness about it. And I stood staring and wondering, and—I must confess—_disappointed_ at this meek-looking, smallish snake being a representative of the terrible, ‘formidable’ picture that had been conjured up. ‘I don’t believe that’s a _Jararaca_!’ were my inward conclusions. ‘I am _sure_ it isn’t! It _can’t_ be. It does not agree in any way.’ Then came the keeper to the cage, to tell me of this new and valuable addition; but I only repeated aloud my already firm convictions.

‘Here’s the gentleman who brought it from Brazil, and he ought to know,’ returned the keeper in justifiable argument as he motioned with his hand towards a stranger by his side. The name of Dr. Arthur Stradling, a Corresponding Member of the Zoological Society, was already known to me. Though personally unacquainted, he had, indeed, through the columns of _Land and Water_, replied to some communications of my own. This informal introduction, therefore, led easily to the exchange of a few words about this contradictory ‘Jararaca,’ the name by which—as he assured me—the snake was known in Brazil. He had not, he said, examined the mouth of this snake during the voyage home, knowing its deadly character; and had simply accepted it as the ‘Jarraracca,’ according to its Brazilian vernacular. I ventured to point out the non-viperine aspect of the so-called ‘deadly’ reptile before us, and suggested that if it were indeed venomous it could only be an elaps, also that there were probably several that were known by this name. This led to a correspondence, both by letter and through the columns of _Land and Water_ (Oct. 1880), on the subject of vernacular names; but as these belong more especially to the ensuing chapter, I need only say here that Dr. Stradling returned to Brazil determined to investigate this confusion of names, and I thus gained a valuable ally in my endeavours to identify some of the perplexing vernaculars of Brazil with the scientific descriptions.

On a subsequent voyage, Dr. Stradling obtained three more of these so-called Jararacas, and described them by letter, and subsequently in _Land and Water_.

Echoing my own perplexities, he asks, ‘_Is_ there such a snake as the _Jarraracca_? When I got three more living specimens of the same this last voyage in Pernambuco, I began to have my doubts, for I could not reconcile them with the description at all. One died, which fact I did not, by ill luck, discover till it was worthless; but I observed, as I thought, a well-developed fang. A few days later a good opportunity presented itself for picking up one of the survivors and examining its mouth; then to my surprise I found that the supposed fang was really a large curved tooth, situated quite out of the natural position of a fang, but symmetric with one on the opposite side. Then I looked at the other one, and finally let both bite me, which settled the matter. I set it down as _Xenodon_ (a harmless snake), and was gratified to find on reaching home that Dr. Günther had pronounced my specimen at the Gardens’ (the one brought the previous September) ‘_Xenodon rhabdocephalus_, the long-headed snake, on its death. But I don’t find any mention of this extraordinary isolated tooth anywhere, though I have a vague idea that Dr. Wucherer, who has perhaps been the most earnest student of the Brazilian Thanatophidia, spoke of it in a communication to the Society some years ago. The real “Jarraracca” is still veiled in mystery.’ I also was ‘gratified’ to find the Corresponding Member of the Zoological Society so generously justifying my doubts about the supposed _Jararaca_, both in his letter to me and in a paper to _Land and Water_, 2d April 1881.

This was the first time I had ever heard of a _Xenodon_, a name which Dr. Günther was then so good as to explain meant ‘strange tooth;’ and he drew a little diagram of the jaw with five simple teeth curving back, and then a long, fang-like back tooth. Strange indeed! _Heterodon_ I knew possessed a large, fang-like tooth, which had caused it to be called ugly names. Now here is more heterodox dentition.

Dr. Wucherer’s account of the _Xenodon_ was discovered in the _Zoological Society Proceedings_ for 1861. He also had been a C.M.Z.S.[112] in the same region, and his report of the curious _Xenodon rhabdocephalus_ is that it is very voracious, feeding chiefly on frogs, but will swallow his friend too, should the latter have hold of one on which he has set his heart. It flattens itself remarkably, and thus gets through a very narrow chink. It is a fresh-water snake, called _Cobra d’aqua_ in Brazil, also _Surucucu_ (from its evil reputation). But Dr. Wucherer says not a word of those fang-like teeth.

Meanwhile Dr. Stradling had most kindly sent me the magnificent specimen of ‘_Curucucu_’ (_Lachesis mutus_), in spirits; and this, together with the investigation of certain other vernaculars, made the _Xenodon_ of only secondary interest in our correspondence until exactly six months afterwards, when, on landing, June 1881, he wrote that he was sending a _Heterodon_ and another _Xenodon_ to the Gardens.

‘Where are the new snakes?’ I asked the keeper, hurrying to the Reptilium early next day.

‘What new snakes, ma’am? There are none fresh since you were last here.’

‘Ah, well, they are coming! Most _interesting_ kinds. I shall wait for them.’

Sure enough, ere long a boy was seen approaching from the office with a ‘box of snakes.’ He also brought the news that the Doctor was expected ‘directly.’

Consigned to their cage, how I hovered about those ‘strange-toothed’ Colubers that long midsummer day! How I wished they would bring their heads close to the glass and yawn the widest of yawns, and how I waited for the ophiological dentist to come and exhibit their ‘fangs!’ for the donor of these valuable acquisitions had been devoting himself to the discovery of antitoxics, and was supposed to be snake-proof, and to do what he pleased with both venomous and non-venomous kinds. But the long midsummer day waxed on, and I gazed at the _Xenodon_ till I knew every mark of his leaf-like pattern; and the day began to wane, and my hopes of seeing the wonderful teeth began to wane also. And I felt I had a sort of claim upon this _Xenodon_, the ‘Jarraracca’ about which we had corresponded.

I had relied so much on having the pseudo-fangs scientifically displayed to me, that when the visitors were departing and the keeper was at liberty, I told him about these strange teeth which I was so anxious to see, and at last persuaded him to open _Xenodon’s_ mouth for me, and to hold it open (which operation the keepers understand very well) while I made the dental examination myself.

After all there was nothing in the shape of a fang to be seen!

‘Posterior tooth long, compressed’! ‘Last tooth very long, compressed, ensiform’! and so on, said the authorities; but nothing of the kind was here! I could see to its very throat, and the rows of tiny palate teeth and the four rows of jaw teeth, all exceedingly small, but never a fang. So I stared and wondered, and then in my bewildered amazement and vexation I passed my little finger along the jaws and _felt_ the upper teeth.

This practical investigation no doubt greatly offended the imprisoned patient, for suddenly down came a pair of regular fangs—they _looked_ like fangs;—and as my finger pressed the jaw on one or on the other side, I saw these fang-like teeth move, vibrate, exactly like the viperine fangs. When my finger was removed, up they went, folded back in their sheath in true viperine fashion. My finger got a slight prick, for they were exceedingly sharp; but knowing there was no venom in them, that did not concern me, and in a few minutes the sensation was gone. But how was it that Dr. Stradling had made no mention of this extraordinary viperine mobility of the fangs? And what kind of jaw must a snake have to move its back teeth in this manner! For we saw in the previous chapters that the mobility of the fangs is in proportion to the diminishing length of the maxillary bone, that the excessive mobility of the viperine fang is owing to the greatly reduced size of that bone, that a slight mobility is observable where the jaw is somewhat less reduced, and so on; but here is a harmless Coluber with a jaw long enough to hold five or six fixed, simple teeth, and then an extremely mobile long one at the back. Can the jaw be divided in the middle? Thus I marvelled.

‘Now let us look at Heterodon.’

But that pretty little snake positively refused to open its mouth; so, fearing to alarm it, or cause it to disgorge its last meal, I did not encourage its forcible detention.

Not to lose a moment, I then and there pencilled a note to Dr. Stradling, begging him to tell me if he had observed anything unusual in _Xenodon’s_ ‘fangs.’ That I had examined them and seen what appeared very extraordinary; but before describing it, was desirous of having my observations confirmed by him.

But the Dr. had been unexpectedly appointed to another ship, which would sail immediately. Many weeks must, therefore, elapse before his reply could reach me.

That day there was but one direction to which my ophidian compass directed my steps, viz. the British Museum; and several days were spent there hunting every possible book to find any mention of _Xenodon’s_ moveable teeth, but in vain. Surely a feature so exceptional would have been described had it been observed. Pardon, kind reader, these many words about ‘so small an affair;’ but you who are naturalists know the peculiar charm of finding ‘something new,’ producing, as Charles Kingsley described, ‘emotions not unmixed with awe,’ that among the happy memories of study or of travel ‘stand out as beacon points.’ It was my great ambition to add ‘something new’ to science. But here was I with a secret ‘discovery,’ and not knowing what to do with it. And ‘if anything should happen’ to _Xenodon_ meanwhile! Then the keeper would be reprimanded. Plainly, courtesy demanded that the secretary of the London Zoological Society should receive an explanation of my infringement of rules; therefore, in a letter to him, I described _Xenodon’s_ whole history. I also wrote a detailed account of _Xenodon_ to a friend who edited a zoological publication, under the delusion that I should be invited to contribute a full, true, and particular account of these wonderful teeth to half the zoological journals of Europe! ‘First observed by C. C. H.!’ But no!

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.

On a second occasion I made a dental examination of the living _Xenodon_ in order to be fully convinced of the nature of its back teeth, and in both instances the fangs were depressed until the snake was provoked into displaying them. It exhibited no spitefulness or attempt to bite, and in both cases folded back its fangs the moment my finger was removed, as if glad that the ceremony was over.

_Heterodon d’Orbignyi_, being a small and delicate snake, was not again enticed to exhibit its jaws; but my forbearance was otherwise rewarded. One day it was dining off a rather large frog, and its mouth, close to the glass, was stretched open to its fullest extent. The frog had disappeared so far as to be within the mouth, wedging it wide open; and I then saw a fang well erected and in use, _moving_, being detached, in fact, from the food. It appeared to be somewhat nearer to the front than _Xenodon’s_ fangs, with perhaps only three or four simple teeth before it. But that it was a sheathed fang and _mobile_ I have no doubt whatever, having seen it very distinctly. I told Tyrrell at the time that _Heterodon’s_ fangs were also moveable; but now for the first time I impart this new secret to the public. _Xenodon_ also greedily seizes upon inconveniently large frogs, but it has never displayed its fangs to me while feeding, as the pretty little _Heterodon_ did. One more singular thing did this little _Heterodon_, and that was to assist itself by coiling its body round an unmanageable frog one day. It did not regularly constrict it in order to kill it; but _when caught_ in the mouth, it helped itself to restrain the straggling limbs by a few coils. Dr. Wucherer affirms that he had never seen its congeners _Liophis_ or _Xenodon_ squeeze or coil themselves round their prey, but _Heterodon d’Orbignyi_ certainly does.

Another peculiarity of the American _Heterodons_ is that of flattening their heads and the upper part of the body when angry or molested. It is this, together with their pseudo-fangs, that have procured them the name of ‘spread-head,’ ‘spreading-adder’, ‘puffing-adder’ or ‘blowing viper’,—because at the same time they hiss violently,—or simply ‘the adder,’ and ‘_blausser_,’ or the blower.

There are several species of them, all, with the exception of _H. d’Orbignyi_, having undeniably ugly, viperish-looking heads, ‘_Anguis capitæ viperino_,’ or ‘_Serpent à la tête de vipère_.’ The snout terminates in a large, conspicuous, recurved scale which gives them a pug-nosed or rather a hog-nosed appearance. Catesby, who was the first to describe the ‘hog-nosed snake,’ said ‘it hath a visage terrible and ugly.’ In _H. niger_ and _H. platirhinos_ this is most apparent. They belong mostly to the New World, both north and south. One in Virginia is called, from its bright markings, the ‘calico snake,’ the word calico in America being applied chiefly to coloured prints used for dresses. Another is called ‘the mountain moccasin,’ the latter name in the United States being applied to venomous kinds.

In the flattening of the head and body, _Xenodon_ and _Heterodon_ approach the cobras; in the strange dentition they approach the vipers; in their true nature they are harmless colubers: thus do we see the wonderful links or gradations between opposite families, which have been such a perplexity to the early naturalist.

The _Heterodons_ have the reputation of ‘feigning death’ when annoyed. This peculiarity has been commented on by many who have experimented upon the snake for this purpose. Holbrooke observed it in _H. platirhinos_, and came to the conclusion that it was done at will. ‘It will deceive its tormentor by feigning death, remaining flat and motionless.’ It otherwise ‘flattens the head and upper part of the neck, which it lifts and waves, hissing loudly.’ This is the true cobra manner. He often worried it and tried to make it bite, when it only projected its head in that menacing way, but with closed mouth. On the contrary, other experimentalists describe it with widely expanded jaws when thus annoyed. In an excellent American magazine, _Science News_, the _Heterodons_ formed the subject of several papers a few years ago. To my friend, Mr. J. E. Harting, I am indebted for some numbers of _Science News_, in which _Heterodons’_ performances are fully described. One, on being intercepted in its retreat, ‘threw its head back with widely expanded jaws; but instead of striking, it turned completely over on its back, remaining stiff and motionless, with jaws fixed in rigid expansion, feigning death.’ Reptilian intellect was, however, insufficient to carry out the feint, inasmuch as its full muscular power was exercised to maintain its position. ‘On concealing myself,’ continues the narrator, ‘it cautiously righted itself and made off; but only to repeat the _ruse_ when again caught.’[115] Dr. J. Schneck, in the March number for the same year, describes a similar action on his worrying them with a switch, when, after making futile efforts to attack, they would seem to bite themselves (which they really never do), and then turn on their backs as if dead. After a few moments of quiet they would turn over and beat a hasty retreat. Several other writers in _Science News_ confirm Holbrooke’s experience, that ‘under no provocation can it be induced to bite.’ Those we have seen at the Gardens verify this; exhibiting an extremely inoffensive nature, though no death-feigning or summersault performances. And I am more inclined to attribute the rigidity to a sort of paralyzed terror than to any pretence of being dead. The same thing is observed in some insects. If you blow on them or alarm them, they will flatten themselves against whatever they may be crawling on, and cling close and stiff as if dead, but presently escape. Some other snakes, also, as well as the _Heterodons_, keep rigidly still as if paralyzed when molested, previous to attempting any escape, though I do not remember any others that turn over on their backs in so singular a fashion.

A few more words about the _Deirodon_ with its still stranger teeth must come in the next chapter.