HANK OF CIRCULAR GROUPS. 347 



sub-genus) and the species. That there is an inter- 

 vening description of circles, however, between families 

 and genera, has been so extensively demonstrated in 

 ornithology that the matter has been set at rest, for it 

 cannot be supposed for a moment that such groups 

 should exist in, comparatively, so small a class as that 

 of Aves, and yet not among true insects, whose numbers 

 exceed those of birds, as much, probably, as in the pro- 

 portion of twelve to one. Following our plan of giving 

 examples, we may cite the divisions of the two families 

 of shrikes and thrushes (418.) as so many sub-families, 

 the genera there named being only typical examples. 

 If the student wishes to see the demonstration of one 

 of these sub-families, the Myotherinee, or ant thrushes, 

 he will find their analysis detailed at some length in 

 " Northern Zoology," p. 168., and also that of the sub- 

 family PiciancB, or the pre-eminently typical wood- 

 peckers, at p. 300. of the same volume. Names desig- 

 nating this description of group are made to terminate in 

 -inae, as a ready mark of distinction from such as, ending 

 in -idse, indicate the names of families. 



(429.) We now come to Genera, of which more de- 

 finitions have been given than of any other group in 

 nature. It is quite unnecessary to repeat, in this place, 

 the various and conflicting opinions of those who by 

 supposing there are no really definite groups in the cre- 

 ation affix to the term a meaning either so vague or 

 so circumscribed as to leave every one at liberty to put 

 their own interpretation upon the alleged definition. 

 A genus, by the old writers, was the first assembling to- 

 gether of species ; but no fixed rules were laid down for 

 determining what degree of variation, among these spe- 

 cies, would exclude them from being ranked under one 

 generic name, or, if laid down, they were so frequently 

 violated,' that, in process of time, the original type seems 

 to have been lost sight of, and a host of other species 

 became associated with it, which frequently bore but a 

 mere outward or remote resemblance thereto. Do what 

 we will to define a genus, or, in fact, any other 



