The Common Adder varies in length, from thirteen or fourteen inches to double that length; and from two to three or even four inches in girth. Its general colour varies considerably: in some it is olive, in others reddish-brown, varying sometimes to an ashy-grey; at other times it is greyish-black. A waving brown or blackish line runs along the back. A row of unequal spots of the same colour is observable on the flanks; the belly is slate-coloured; the head nearly triangular, a little larger than the neck, obtuse and truncated in front, and covered with granulated scales. Six small plates cover the muzzle, two of which are perforated for the nostrils, which are lateral, forming a blackish spot. Above is a sort of V shape, formed by two black bands. The upper jaw is a white ground, spotted with black; the lower jaw is yellow. The eyes are small and sharp, edged with black. The tongue is long, grey, and forked. Adders are met with in the wooded, stony, and mountainous regions of southern and temperate Europe--in France, Italy, England, Germany, Prussia, Sweden, Poland, and even Norway. They are met with in the heaths near London and in the neighbourhood of Paris; they are met with at Montmorency, and in the forest of Fontainebleau. They feed upon Lizards, Frogs, mollusks, worms, insects, and small mammalia, such as Field-mice, Shrews, and Moles. They pass the winter and early spring in a state of torpor in deep hollows, where they are sheltered from the cold. It is not unusual to find several Adders coiled up together in one heap, entwined and intimately interlaced together. The movement of Adders is abrupt, slow, and irregular. They appear to be shy and timid creatures, shunning the day, and only seeking their food in the evening. The young come into the world naked and living: so long as they are maintained within the mother, they are enclosed in eggs with membranous shells. Soon after their birth the young Vipers, whose length does not exceed six or seven inches, are abandoned by the mother, and left to shift for themselves. They do not, however, acquire their full development till they are six or seven years old. Adders are justly considered objects of fear and horror both to Men and to other animals. They carry with them a formidable apparatus, of which it is important that both the structure and the mode of action should be known. This Venemous apparatus is composed of three parts--the secreting glands, the canal, and the hooked fangs.