INTRODUCTION gj 



Families almost every feature in the skeleton of which points to a separa- 

 tion. Common sense revolts at the acceptance of any scheme which 

 involves so many manifest incongruities. With far greater pleasure 

 we would leave these investigations, and those on certain other muscles, 

 as well as on the Disposition of the deep plantar Tendons, and dwell upon 

 his researches into the anatomy of the Passerine Birds with the view to 

 their systematic arrangement. Here he was on much safer ground, and 

 it can hardly be doubted that his labours will stand the test of future 

 experience, for, though it may be that all his views will not meet with 

 ultimate approval, he certainly made the greatest advance since the days 

 of Miiller, to the English translation of whose classical work he added (as 

 before mentioned) an excellent appendix, besides having already con- 

 tributed to the Zoological Proceedings between 1876 and 1878 four 

 memoirs replete with observed facts which no one can gainsay. As his 

 labours were continued exactly on the same lines by Forbes, who between 

 1880 and 1882 published in the same journal six more memoirs on the 

 subject, it will be convenient here to state generally, and in a combined 

 form, the results arrived at by these two investigators. 



Instead of the divisions of Passerine Birds instituted by Miiller, Garrod 

 and Forbes having a wider range of experience considered that they had 

 shewn that the Passeres consist of two primary sections, which the latter 

 named respectively Desmodacttli and Eledtherodactyli, from the facts 

 discovered by the former that in the Euryleemidaz (Broadbill), a small 

 Family peculiar to some parts of the Indian Eegion, and consisting of 

 some ten or twelve species only, there is a strong band joining the muscles 

 of the hind toe exactly in the same way as in many Families that are not 

 Passerine, and hence the name Desmodadyli, while in all other Passerines 

 the hind toe is free. This point settled, the Eleutherodadyli form two 

 great divisions, according to the structure of their vocal organs ; one of 

 them, roughly agreeing with the Clamatores of some writers, is called 

 Mesomtodi, and the other, corresponding in the main, if not absolutely, 

 with the Oscines, Polymyodi, or true Passeres of various authors, is named 

 AcROMYODi — " an Acromyodian bird being one in which the muscles of 

 the syrinx are attached to the extremities of the bronchial semi-rings, a 

 Mesomyodian bird being one in which the muscles of the syrinx join the 

 semi-rings in their middle." Furthermore, each of these groups is sub- 

 divided into two : the Acromyodi into " normal " and " abnormal," of which 

 more presently ; the Mesoviyodi into Homceomeri and Heteromeri, 

 according as the sciatic or the femoral artery of the thigh is developed — 

 the former being the usual arrangement among Birds and the latter the 

 exceptional. Under the head Heteromeri come only two Families, but 

 these Garrod was inclined to think should not be considered distinct. 

 The Homoeomeri form a larger group, and are at once separable, on account 

 of the structure of their vocal organs, into TracheojjJwnx (practically 

 equivalent to the Tracheophones of Miiller) and Haploophon^ (as 

 Garrod named them) — the last being those Passeres which were by Miiller 

 erroneously included among his Picarii, namely, the Tyrannidas. (Tyrant) 

 with Rupicola (Cock-of-the-Rock) and Pitta. To these are now added 

 Families not examined by him, — but subsequently ascertained by Forbes 



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