64 Retrospective Criticism, 



man's difRculty; how are we, in writing or conversation, to 

 indicate subgenera? I think that, for common purposes, it 

 is not necessary to do so at all. When the name of a genus 

 is mentioned, a knowledge of the larger groups in which it is 

 contained is presupposed. If, therefore, we carry the standard 

 of our genera too low, it is probable that none but those few 

 who have leisure to make themselves perfect in zoology will 

 know the class or order of a genus which another person may 

 casually mention. If a naturalist at Calcutta is told that the 

 i^ringilla coe^lebs is common in England, he at once recognises 

 the general characters of the bird ; but if it were called Schiza 

 coe'lebs, as Mr. Blyth would call it, it is a great chance 

 whether he would be the wiser for the information. But, if 

 greater accuracy be required, the informant may add that it 

 belongs to section A or B ; and, if he were describing a new 

 species, he would, of course, either indicate the section, or 

 describe it with sufficient accuracy to enable any one to refer 

 it to the right one. 



In offering these remarks, I am far from desiring the Lin- 

 naean genera to be retained unaltered, but merely wish the 

 practice of forming new genera not to be carried too far. 



Mr, Newman says (p. 480.) that the orders i^erae, ^cci- 

 pitres, and Coleoptera are not of the same value, because 

 the latter contains many groups analogous to the two for- 

 mer, and others quite different. He seems to have over- 

 looked the remark of Decandolle, in Mr. Jenyns's paper 

 (p. 389. note *), " that the same characters are not of equal 

 value in different groups." Hence there can be no doubt 

 that it is far more natural to found the orders of insects 

 upon the structure of their wings, than to put Fespa, Libel- 

 lula, and Cicindela into one order, on the ground of being 

 rapacious ; and ^'pis, Papilio, and Chrysomela into another, 

 because they are herbivorous. 



Mr. Newman objects to uniting the Cetacea with the other 

 Mammalia ; but if we attend not only to the number of charac- 

 ters which they have in common, but to the value of those 

 characters, that is, to the high station which they hold in the 

 scale of existence, there can be little doubt that this is a 

 natural union. The claim of the Marsupialia, and especially 

 the Scansores, is more doubtful; founded, as they are, on 

 single characters only, and those not, perhaps, of very great 

 importance. I am. Sir, yours, &c. — H, E. Strickland. 



Classification (VI. 385. 481— 488.)— Mr. Newman (p. 480.) 

 appears to me to have misunderstood the observations of 

 Mr. Jenyns. (p. 385.) Mr. Jenyns refers, I presume, to a plan 

 similar to that adopted in botany; where subgenera (or, as they 



