British Reptiles and Batrachians

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1878 Excerpt: ... we can scarcely affirm that a frog is brown, or green, or yellow. When just emerging from the mud it is so dark that the black spot is scarcely seen, and when among grass or plants the tint is greenish. These changes were always observable in my little Batrachian family, and they were very frequent. One little frog that liked to keep above and in the light was of a golden tint, and the others that preferred hiding were much darker; and though all changed their tints, each was, under all circumstances, sufficiently distinct for me to recognise it. The change of colour is protective. Not that we may suppose that a frog deliberately resolves to turn brown or black on dark ground, or green when in the grass, but that there is something in the colour of contiguous objects which does act upon the skin is very certain. Claus tells us that the colourings of its skin are due to pigment cells in the cutis, and that the changes of colour axe caused by changes in the form of the cells. It is evident, therefore, that an external influence, and not a voluntary operation, acts on the cells; though the terms imitation and mimicry have been used in describing changes of colour in some insects and birds. The skin of a frog is also richly supplied with nerves, and is to be regarded as the seat of the tactile sense. A larger and older frog, in its second summer, gave me frequent opportunities of remarking its extreme sensitiveness, starting at any sudden or jarring sound, as a nervous person starts at a gun going off, or a door slamming. This frog, known as Froggin (while the very young ones were Froggies ), had the run (or jump) of a glazed off-shoot to our house, called in the house-agent's advertisement Co...