126 NORTHERN ZOOLOGY. 



These objections have had their due weight, and they suspended our judg- 

 ment on this matter for some time. The first, indeed, is so strong, that if our 

 views on the Insessores are correct, it can only be accounted for by that property 

 which may belong to typical groups, adverted to in our introductory remarks ; that 

 is, of gradually approximating, in proportion as we contract our views, from order 

 to family, from family to sub-family, and from sub-family to genus : so that, in 

 cases where every conceivable intervening form is known, what was in larger 

 groups but a relation of analogy, finally becomes one of absolute collateral 

 affinity ; a relation, however, which by no means disturbs the true or direct affinity 

 by which each of these groups revolve, and are united in their own proper circles. 

 An instance of the same intimate relationship may be cited between the true 

 Merulce and the Nightingale-warblers (Philomelinw), in the family of Sylviadw ; two 

 groups, whose juxta-position is precisely the same as Thamnopkilus and Myothera, 

 and which, in like manner, evince so close a resemblance, that the Sylvia 

 turdo'ides of M. Temminck is described, in the first edition of that author's valuable 

 work on the Birds of Europe, as a true Turdus, under the name of Turdus arun- 

 dinaceus ; in which genus it has also been placed by Dr. Latham and others. 

 Here, then, is a case in point, where the analogy between the corresponding points 

 of two family circles is so close, as to amount to what we should be justified in 

 calling, under other circumstances, an absolute and direct affinity. That such, how- 

 ever, is not the case in regard to the Sylvia turdo'ides, as connecting the Merulidee 

 with the Sylviadce, will subsequently appear ; and, in respect to the supposed 

 affinity between the Pipra pileata and the sub-genus Prionops, the evidence to 

 be adduced is much more in favour of their direct analogy. 



We shall close these remarks — already extended, perhaps, to too great a 

 length — with a hope that they may awaken the attention of ornithologists to these 

 singular relations between the Thamnophilinw and the Myotherinw ; not so much to 

 elucidate the groups themselves, as to investigate whether the typical circles, in 

 small assemblages of natural objects, do not insensibly acquire additional properties 

 beyond those which are possessed by larger groups. The only writer in whose 

 works we can trace any opinion on this intricate subject, or who appears to have 

 given an intimation that analogies may blend into affinities, is our friend 

 Mr.Haworth, who, in his new binary arrangement of the Macrurous Crustacea {Phil. 

 Mag.), makes the following observation : " The first articles of every dichotomy 

 are often merely analogies ; but that these insensibly, as we go down the table, 

 to arrive at the genera, lessen, and blend into the closest affinities." Whether this 

 passage, however, can be cited as strengthening our own suspicions, we cannot 



