Page:Encyclopædia Britannica, Ninth Edition, v. 18.djvu/50

40 OKNITHOLOGY may be not unreasonably supposed to have a strong feeling as to its efficacy for systematic ends. It was in favour of an arrangement based upon the muscles of the thigh, and elaborated by him in 1874, that he gave up the arrange ment he had published barely more than a year before based upon the conformation of the nostrils. Neverthe less it appears that even the later of the two methods did not eventually content him, and this was only to be expected, though he is said by Forbes (/6w, 1881, p. 28) to have remained " satisfied to the last as to the natural ness of the two main groups into which he there divided birds" Homalogonatx and Anomalogonatse. The key to this arrangement lay in the presence or absence of the ambiens muscle, " not because of its own intrinsic import ance, but because its presence is always associated with peculiarities in other parts never found in any Anomalo- gonatous bird. Garrod thought that so great was the improbability of the same combination of three or four different characters (such as an accessory femoro-caudal muscle, a tufted oil-gland, and ca^ca) arising independently in different Birds that similar combinations of characters could only be due to blood-relationship. The ingenuity with which he found and expressed these combinations of characters is worthy of all praise ; the regret is that time was wanting for him to think out all their consequences, and that he did not take also into account other and especially osteological characters. Every osteologist must recognize that the neglect of these makes Garrod s proposed classification as unnatural as any that had been previously drawn up, and more unnatural than many. So much is this the case that, with the knowledge we have that ere his death he had already seen the need of introducing some modifications into it, its reproduction here, even in the briefest abstract possible, would not be advisable. Two instances, however, of its failure to shew natural affinities or differences may be cited. The first Order G al/iformes of his Subclass Homalogonatx is made to consist of three "Cohorts" Strutkiones, Galliiiacese, and Psittaci a somewhat astonishing alliance ; but even if that be allowed to pass, we find the second "Cohort" composed of the Families Palamedeidx, Gallinse., Rallid.se, Otididse, (containing two Subfamilies, the Bustards and the Flamingoes), Musophagidsn, and Cuculidie. Again the Subclass Anomalogonatx includes three Orders Pici- formes, Passeriformes, and Cypseliformes a preliminary to which at first sight no exception need be taken ; but immediately we look into details we find the Alcedinidx placed in the first Order and the Meropidx in the second, together with the Passeres and a collection of Families almost every feature in the skeleton of which points to a separation. Common sense revolts at the acceptance of any scheme which involves so many manifest incongruities. With far greater pleasure we would leave these investiga tions, 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 already mentioned) an excellent appendix, besides having already contributed 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 experi ence consider that they have shewn that the Passeres con sist of two primary sections, which the latter named respectively Desmodactyli and Eleutkerodactyli, from the facts discovered by the former that in the JSurylsemidse, or Broadbills, a small Family peculiar to some parts of the Indian Region, and consisting of some nine or ten 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 Eleutlierodadyli form two great divisions, according to the structure of their vocal organs ; one of them, roughly agreeing with the Cla- matores of some writers, is called Mesomyodi, 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 subdivided into two : the Acromyodi into "normal" and "abnormal," of which more presently; the Mesomyodi 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 Hetero meri come only two Families the Cotingidse. (Chatterers) and Pipridx (MANAKINS, vol. xv. p. 455) of most orni thologists, 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 struc ture of their vocal organs, into Tracheophons& (practically equivalent to the Tracheophones of Miiller) and Haploo- pkonse (as Garrod named them) the last being those Passeres which were by Miiller erroneously included among his Picarii, namely, the Tyrannidoe (see KING-BIRD, vol. xiv. p. 80) with Bupicola, the Cocks-of-the-Rock. To these are now added Families not examined by him, but subsequently ascertained by Forbes to belong to the same group, Pittidae, Philepiltidse, and Xenicidx (more pro perly perhaps to be called Acanthisittidai), and it is remarkable that these last three Families are the only members of the Mesomyodi which are not peculiar to the New World nay more, if we except the Tyrannidx, which in North America occur chiefly as migrants, not peculiar to the Neotropical Region. The Tracheo- phonse are held to contain five Families Furnariidss Oven-birds), Pteroptochidss (TAPACULOS, q.v.), Dendro- colaptidx (Piculules), Conopophagidse, and Formicariidx (Ant-Thrushes). Returning now to the Acromyodi, which include, it has just been said, a normal and an abnormal section, the latter consists of birds agreeing in the main, though not absolutely, as to the structure of the syrinx with that of tike former, yet differing so con siderably in their osteology as to be most justifiably separated. At present only two types of these abnormal Acromyodi are known Menura (the LYRE-BIRD, vol. xv. p. 115) and Atrichia (the SCRUB-BIRD, q.v.}, both from Australia, while all the remaining Passeres, that is to say, incomparably the greater number of Birds in general, belong to the normal section. Thus the whole scheme of the Passeres, 1 as worked out by Garrod and Forbes, can be 1 It is right to observe that this scheme was not a little aided by a consideration of palatal characters, as well as from the disposition of some of the tendons of the wing-muscles.