WAENING COLORATION. 185 



can secrete a poisonous substance, but it points to the more 

 deadly properties of tbe frog's skin. It is well known that 

 the skin of the common toad produces a secretion which will, 

 if injected into the body of a fowl, cause death. This was 

 proved by the late M. Paul Bert ; * it is probably common 

 among Amphibia, but does not necessarily lead to their being 

 refused as food. Even toads are taken by certain birds, as 

 I have myself proved, though the toads were not perhaps 

 relished so much as frogs are. Xenopu& is not a more con- 

 spicuous animal than the common toad ; they are apparently 

 both instances of a disagreeable quality being concealed by 

 a well-protected exterior. The small newt is also eaten by 

 several birds, but with no particular signs of enjoyment. 



Bright Colours not always used as a Warning. 



Although it has been proved, particularly among cater- 

 pillars, that a conspicuous coloration is often a mark of 

 inedibility, this is thought to be not always the case ; I do 

 not now refer to brilliant colours, distinction of sex, or what 

 has been thought to be the result of sexual selection, — this 

 part of the subject will be gone into later. 



Mr. Savile Kent, in a very interesting presidential address 

 to the Royal Society f of Queensland, relates an instance of 

 commensalism between a fish and a sea anemone. Com- 

 mensalism, it should be said, is a term used to express a 

 kind of parasitism where the parasite recompenses its host 

 for favours received by material benefits rendered in return. 

 Among the coral reefs in the neighbourhood of Thursday 

 Island an enormous sea anemone occurs ; it is at least two 



'* Prof. Howes informs me that he has repeated. the experiment, and 

 veriiied Paul Bert's results. 



tNov. 22nd, 1891. For the loan of this pamphlet I am indebted to 

 Prof. Howes. 



