Thus we find every gradation both in number and in form until we come to the true fang, the ‘murderous tooth’ of the terrible cobra, the _hydrophidæ_, and the _viperidæ_. And noteworthy it is that the fewer the teeth in the maxillary bone the more terrible are they. Fig. A of the four illustrations given opposite is the jaw-bone of the Indian Rat snake, _Ptyas mucosus_, already ‘honourably mentioned’ in these pages. The illustration being taken from Fayrer’s _Thanatophidia_, may be received as a faithful representation. This conveys a good idea of jaws generally in non-venomous snakes of that size, say from six to ten feet long. In some of the smaller kinds the jaw and palate teeth are so fine as to be almost imperceptible to the naked eye. To the touch they feel like points of the finest pins. Draw your finger along or press it against a row of ‘minikin pins,’ and you will form a correct idea of these tiny weapons. I have often _felt_ when I could not _see_ them in the mouth of a small harmless snake. Pass the tip of your little finger gently along them towards the throat, and they are almost imperceptible even to the touch; but in withdrawing your finger _against_ the points, you feel how excessively fine they are. The accompanying illustrations are from nature, and exemplify the various lengths of jaw in four snakes, not differing very greatly in size. [Illustration: Four jaws. From Fayrer’s _Thanatophidia of India_.] _Fig. A._ _Ptyas mucosus_, with simple teeth only. That they are not very regular is probably owing to the stages of growth in those that have replaced others. _Fig. B._ A venomous snake, _Bungarus_, the ‘Krait,’ with a fixed fang in front and a few simple teeth behind it. _Fig. C._ Jaw of the cobra, with a longer fixed fang, and one or two simple teeth behind it. _Fig. D._ The shortest jaw of them all, that of the Indian viper _Daboia_, in which the maxillary is reduced to a mere wedge of bone. These, with four or five reserve fangs, are here folded back ‘depressed.’ A few palate teeth are also seen. Having given a slight sketch of the various forms of dentition, and arrived at ‘fangs,’ we may recapitulate, in what Nicholson calls ‘roughly speaking,’ four stages of development in these latter. _First_, the ‘fangs’ of the harmless snakes, such as _Lycodon_, _Xenodon_, _Heterodon_, etc., which have no poison gland, but whose saliva may be slightly and occasionally injurious. _Secondly_, those having a salivary gland secreting poison and a grooved fang in front of some simple teeth, _Hydrophidæ_. _Thirdly_, the maxillary bone shorter, bearing one poison fang with a perfect canal, and one or two teeth behind it. In some of these there is a slight mobility. _Fourthly_, the maxillary bone so reduced as to be higher than long, and bearing only a single tooth, viz. a long, curved, and very mobile fang, _Viperina_.