. The world of animal life. Zoology. 300 THE WORLD OF ANIMAL LIFE VIPERS (Family ViPERlD^) The Adder, which is the third British snake, is a good type of the Viper family. It may easily be distinguished from the two already mentioned by the zigzag chain of lozenge-shaped black markings which runs along the spine. This snake lives chiefly upon heaths and sandy commons, and is fond of lying coiled up in the sun, in which position it bears so strong a resemblance to a piece of twisted stick, that a passer-by might easily tread upon it before discover- ing its real nature. It is a venomous snake,
. The world of animal life. Zoology. 300 THE WORLD OF ANIMAL LIFE VIPERS (Family ViPERlD^) The Adder, which is the third British snake, is a good type of the Viper family. It may easily be distinguished from the two already mentioned by the zigzag chain of lozenge-shaped black markings which runs along the spine. This snake lives chiefly upon heaths and sandy commons, and is fond of lying coiled up in the sun, in which position it bears so strong a resemblance to a piece of twisted stick, that a passer-by might easily tread upon it before discover- ing its real nature. It is a venomous snake, and a wound from its poison-charged fangs is sufficient to cause serious illness, and has occasionally been known to result even in death. Head and Tail of Common ^he fangs of a viper are very curiously Viper formed. They are situated in the upper jaw, one upon either side, and lie back upon the roof of the mouth when they are not required for use. Were it not for this provision, the snake would experience great difficulty in swallowing its food. Each fang, however, is surrounded by strong muscles, which throw it forward when the head is raised to strike, and hold it firmly in position until after the blow has been delivered. Just behind the sharp point of each fang is a tiny hole, shaped somewhat like the eye of a needle. This hole opens into a channel which runs through the tooth, and communicates at its base with a small sac, or vessel, in which the poison is contained. It will thus be seen that, when the stroke is delivered, the pressure upon the tooth forces a small drop of poison out of the sac and through the channel, and so into the flesh of the victim. The poison fangs of a viper are nearly transparent, and are almost as brittle as glass. If one of them should be broken, however, there is always a new one lying beneath it in readiness to take its place. If the head of a viper be carefully dissected,. Please note that these images are extracted from scanned page images
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectzoology, bookyear1910
