Page:The Zoologist, 4th series, vol 3 (1899).djvu/572

542 nose." The Horned Frog (Ceratobatrachus guentheri) of the Solomon Islands is described by Mr. Guppy to so closely imitate its surroundings, both in colour and pattern, that on one occasion he captured a specimen by accidentally placing his hand upon it when clasping a tree. This species is so variable in colouration and in the integuments, that Mr. Boulenger has remarked, "Out of the twenty specimens before me no two are perfectly alike." This is probably a case of what is here considered active mimicry.

Birds exhibit many illustrations of active mimicry. A recent writer in 'The Zoologist' called attention to some peculiar "attitudes of a Little Bittern observed in captivity." The real meaning of the attitudes of this bird (Botaurus minutus) seem only to have been understood by the then editor, Mr. Harting, who thus comments on the same:—"The inference to be drawn from these remarks is that the curious attitudes adopted by this bird, on finding itself observed, are assumed in the exercise of what may be termed the instinct of self-preservation, and in a state of nature must tend materially to favour its concealment. Whether it be standing in or near a reed-bed, erect, with neck preternaturally elongated and beak pointed upwards, or crouching against a riverside tree-stump, the attitude is calculated to deceive the eyes of all but the keenest observers, especially since the colour of the bird's plumage harmonizes in a remarkable degree with that of the natural surroundings." Mr. Hudson has made a similar remark concerning the Common Bittern (Botaurus stellaris). "His buff and yellow and chestnut colour, mottled and barred and pencilled with black and brown, gives him a strange tigrine or cat-like appearance; it is a colouring well suited to his surroundings, where yellow and brown dead vegetation is mixed with the green, and the stems and loose leaves of the reeds throw numberless spots and bars of shade beneath. Secure in its imitative colouring, the Bittern remains motionless in its place until almost trodden upon." A very similar pro-