542 THE ZOOLOGIST. 



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.f 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 con- 

 sidered 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 vegeta- 

 tion 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- 



* ' Natural Science,' vol. ix. p. 299. f ' The Solomon Islands,' p. 317. 



I Ibid. p. 316. § ' Zoologist,' 3rd ser. vol. xviii. p. 456. 



|| ' British Birds,' p. 225. — The same writer has given a vivid description 

 of a similar habit of an Argentine Heron (Ardetta involucris), and refers to 

 " a marvellous instinct that makes its peculiar conformation and imitative 

 colour far more advantageous than they could be of themselves " (P. Z. S. 

 1875, p. 629-31). 



