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.’