071 designating Genera and Subgenera, 99 



minor groups, each of which has some additional characters 

 peculiar to itself, of less importance than those common to 

 all. Now, it is perfectly arbitrary in what point of view we 

 choose to consider these three new groups ; we may either 

 affix names to them or not ; we may call them genera, if we 

 please, or subgenera, or mere sections of the old genus A^r^ 

 dea : but what we must noi do (and here, I would observe, is 

 the principal ground of my complaint) is, having determined 

 them to be genera, first to abolish the original group ^^rdea, 

 and then to place them on the same footing with Cic6nia and 

 Platalea *, in this manner, — 



^rdeidae 



A'rdea. Botauras iVycticorax Ciconia Platalea; 



or, raising ^'rdea to the rank of a family, and the group 

 which w^e here call ^rdeidae to one of a still higher deno- 

 mination, not to raise Ciconia and Platalea also ; for these 

 three groups, ^Vdea, Ciconia, and Platalea, having been 

 assumed to be of equal value, it is clear that, whatever rank 

 we assign to one of them, we must assign the same to all. 



I am unwilling to extend this .communication, or I should 

 make some comment on the objections which Mr. Newman 

 has brought forward (VI. 485.) against the expressions which 

 I adoptecl in my former article. [VI. 385.] I shall simply 

 observe, that, when I talk of principles of classification, I do 

 not mean principles of my own setting up, as that gentleman 

 seems to think, but such as have been laid down by those 

 who have studied most deeply the philosophy of the science, 

 and such as are generally acknowledged by all professed 

 naturalists. Of this nature is the only principle to which I 

 had occasion to allude ; viz., thai all groups bearing the same 

 title shoidd be groups of the same value. 



I conceive that every systematist would assent to this prin- 

 ciple, at the same time that no one would ever think of assert- 

 ing that it was now, for the first time, brought forward and 

 offered to his notice. 



L. Jenyns. 

 Swaffham BulbecJc^ Cambridgeshire^ 

 Jan, 14. 1834. 



* The arrangement adopted, not merely in Mr. Stephens's continuation 

 of Shaw's Zoology, to which reference was before given [VI. 388.], but in 

 the latest ornithological work which has appeared in this country. See 

 Selby's IllusU of Brit. Or?i., vol. ii. (Water Birds) p. 8. &c. 



H 2 



