88 



THE ZOOLOGIST. 



account of their offensive odour, and moreover that a knowledge 

 of edible and inedible forms could be transmitted by heredity. 

 Mr. Wallace, the author who conjointly propounded the theory 

 of Evolution with Mr. Darwin, in the Linnean ' Journal ' in 

 1858, has likewise described and figured similar variations in 

 the females of certain butterflies in the Malayan Archipelago.* 

 Darwin states that it is in the largest genera or groups that the 

 variations are most marked, both in plants and animals, mainly 

 because such afford a wider area for the action of the law. 



[Fritz Muller has given a different interpretation of this con- 

 dition from that of Bates, for he thinks that the object of the 

 mimicry is to reduce the danger from attacks of young and in- 

 experienced enemies, which have to acquire the necessary know- 

 ledge. This author has further advanced an interesting series 

 of facts in connection with the structure and development of the 

 Crustacea, which he can only explain by Darwin's theory.] t 



Prof. Louis Agassiz, on the other hand, maintained that all 

 that can be proved is that there exists a considerable difference 

 amongst individuals of one and the same species. Let anyone, 

 he said, familiar with the fossil oxen and dogs compare them 

 with the modern races of these genera, and he will find no 

 correspondence whatever between them, for the simple reason 

 that they do not owe their origin to the same causes. This 

 author, however, advocated the specific distinctions of the various 

 races of men, and was of opinion that they could not have 

 all sprung from a single pair. He was supported by Dr. Hunt, 

 who stated that there is as good reason for classifying the Negro 

 as a distinct species as there is for making the ass a distinct 

 species from the zebra ; and if in classification intelligence is 

 taken into consideration, there is a far greater difference between 

 the Negro and the European than between the gorilla and the 

 chimpanzee. Darwin's theory at least would give a single origin 

 to man, while that of the foregoing authors who adhere so much 

 to the original and independent doctrine of Creation assigns a 

 multiple origin to man. 



Some, like the Duke of Argyll, affirm that many structures 

 (e.g. the feathers of the Humming-bird) have been created for 



* And previously about new species (Ann. Nat. Hist. 2nd ser. vol. xvi. 

 p. 3 84, 1855). 



| See also Wallace on 4 Natural Selection,' 1870 (Macmillan & Co.). 



