598 Descriptions of the Groups of Birds 



form extends, during summer, nearly throughout Asia, Eu- 

 rope, and Africa, including some of the islands of the Indian 

 ocean ; the number of species, however, would appear to be 

 limited to two or at most three, which are very intimately al- 

 lied, and barely distinguishable. 



Having now brought my descriptions of Strepitores Syn- 

 dactyli to a close, I may avail myself of this opportunity to 

 remark, that, since treating of the Cylindrirostres, I have se- 

 veral times heard the jarring note of the great Dacelo, in the 

 Zoological Gardens : it consists of a long, continuous, shak- 

 ing, and very loud harsh cry, considerably modulated in the 

 course of its delivery, but always exactly the same at each 

 repetition : considering the simple structure of its vocal ap- 

 paratus, which may be presumed to be similar to that of all 

 other Strepitores, the modulation of tone adverted to is much 

 greater than would perhaps have been anticipated. 



In corroboration of an opinion, also, which I have express- 

 ed, that probably none of the Strepitores require to drink, it 

 may be remarked that Azara states, of his captive motmots, 

 that he never saw one attempt to do so ; which is the more 

 worthy of notice in this instance, because the bill and tongue 

 of those birds are not (as in the Cylindrirostres, and both 

 tribes of Buceroides), of a structure ill adapted to take up wa- 

 ter. In this, therefore, as in several other particulars, we dis- 

 cern an analogy, if not relationship, between the Strepitores 

 and Raptores, which orders I have alwaysplaced in apposition. 



Finally, it may be remarked, here, that Mr. Swainson has, 

 I perceive, been somewhat captious in quoting an assertion 

 of mine (see p. 497) respecting the distribution of the Cylin- 

 drirostres ; the import of w r hich he has in great measure mis- 

 understood, and might therefore have moderated his exulta- 

 tions, since this very subordinate item of the general subject 

 of my communication (by no means affecting the determina- 

 tion of the main question at issue, that of accurate classifica- 

 tion based on affinities), appears to be all that even he can 

 venture to call in question, — a circumstance not the less sa- 

 tisfactory, as some novel facts (even to "experienced ornitho- 

 logists" ) and generalizations were contained in the paper 

 which he refers to, certain of which, he cannot but have re- 

 marked, are utterly and very widely irreconcileable with his 

 published views respecting the affinities of particular genera, 

 that of the todies [Todus) for instance, more especially, which 

 he may ponder with some considerable advantage. — What I 

 obviously intended was (in the passage cited), that, of the en- 



