1 44 Journal of Travel and Natural History 



In last number of this Journal, in a notice of Dr Wyman's views of 

 the symmetry and homology of limbs, the reader will find facts 

 mentioned which go to prove the presence of a magnetic or 

 electrical polarization in the development of the embryo of 

 vertebrate animals. We are fearfully and wonderfully made, 

 and there are many things in the making of which we have 

 as yet no idea — the distribution of colour one of them. If 

 the theory of natural selection does not give a satisfactory 

 explanation, why the colour of animals corresponds with that 

 of the district in which they live, then neither will it give one 

 in the cases of mimicry by one animal of the pattern of colour or 

 appearance of another. We believe that more of the instances of 

 mimicry than is usually allowed are explicable on the ground of 

 actual affinity between the imitator and the imitated ; others, per- 

 haps, by the colour of the species having been produced under 

 similar original conditions. A gaudy butterfly, of a staring pattern, 

 may not, when taken separately, look as if very much in harmony 

 with the scenery where it was produced ; but seen alive in its 

 native woods it no longer appears so. There it is natural, and, if 

 we give the fancy vein it would not be difficult to imagine a mix- 

 ture of flower and foliage, dewdrop and sunshine, making a gor- 

 geous eff'ect, as bright and not unlike the most gaudy butterfly ; 

 and if to that influence the pattern is due, in one instance, similar 

 causes might produce similar results in another, as in the case of 

 the colour of the animals in the desert, &c. These resemblances, 

 taken from tropical forests, may be mere hamionious representa- 

 tions of common general effect. Still, there remain many most 

 remarkable imitations, both in form and colour, which are not so 

 explicable ; but in most of these we know of no habit of life or 

 advantage derived from the similarity, which could be explained by 

 referring the resemblance to natural selection. The cases where 

 such a reason has been assigned are very few, and at least requiring 

 more investigation before it can be said that it accounts for the 

 resemblance on the ground of natural selection. 



In examining Mr Wallace's able paper we have not put his 

 cases under any critical examination. We have taken his facts as 

 stated by himself He is most careful and accurate in all matters 

 falling under his own observation ; but we think his fondness for 

 generalizing sometimes leads him to accept as settled and admitted 

 statements which are only conjectural hypothesis not yet generally 

 allowed. For example, he adopts the statement as a proved fact 



