INTRODUCTION 93 
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 DESMODACTYLI and ELEUTHERODACTYLI, from the facts 
discovered by the former that in the Hurylemide (BROADBILL), a small 
Family peculiar to some parts of the Indian Region, 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 Desmodactyli, while in all other Passerines 
the hind toe is free. This point settled, the Hlewtherodactyli 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 
Mesomyopt, and the other, corresponding in the main, if not absolutely, 
with the Oscines, Polymyodt, or true Passeres of various authors, is named 
AcromyopI—“‘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 Mesomyodt into Homa@omErt and HErTEROMERI, 
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 Heteromert come only two Families, but 
these Garrod was inclined to think should not be considered distinct. 
‘The Homeomeri form a larger group, and are at once separable, on account 
of the structure of their vocal organs, into Tracheophonx (practically 
equivalent to the TRAcHEoPHONES of Miiller) and HAPLoopHONz (as 
Garrod named them)—the last being those Passeres which were by Miiller 
erroneously included among his Picarii, namely, the Tyrannidxe (Tyrant) 
with Rupicola (Cock-oF-THE-Rock) and Pirra. To these are now added 
Families not examined by him,—but subsequently ascertained by Forbes 
h 
