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Show 122 MR. A. H. GARROD ON THE MUSCLES OF BIRDS. [Feb. 3, a. The Anseres include four families, (I) the Anatida, (2) the Spheniscida, (3) the Colymbida, and (4) the Podicipidee. With the exception of the Podicipidae, they agree in having a formula A B. X, an ambiens muscle, caeca to the intestine (except Mergellus, in which there is only one small caecum), two carotids, a very elongate great pectoral muscle, which meets its fellow of the opposite side above the symphysis furculae in a median raphe, and a tufted oil-gland. The Podicipida have for formula B. X ; the ambiens is absent, as is frequently the semimembranosus ; the left carotid only is present; there are caeca coli and a tufted oil-gland. /3. The Nasuta, including the Storm- and true Petrels. I have not dissected Diomedea. They are divisible into two subfamilies :- 1. The Storm-petrels, with formula A B. X Y , no caeca, a tufted oil-gland and a peculiar sternum. The ambiens does not seem to be always developed. The great pectoral is double. 2. The Fulmarida, with formula A B. X, the ambiens muscle present, two short caeca, a tufted oil-gland, and a characteristic sternum. Bulweria is exceptional in having its formula A. X, and therefore quite different from that of the Storm-Petrels. The great pectoral is double. The order C I C O N I I F O R M E S may be divided into five cohorts of somewhat different importance :- 1. The Pelargi, with formula A. X Y, an ambiens muscle, a tufted oil-gland, intestinal caeca, and a double great pectoral muscle. 2. The Cathartida, with formula A. X Y, an ambiens muscle, no caeca, a nude oil-gland, and a double great pectoral muscle. 3. The Herodiones, with formula A . X Y or X Y , no ambiens muscle, a single caecum coli, and a tufted oil-gland. 4. The Steganopodes, which do not form so natural a family, in my eyes, as in those of many ; for their myological formula is not the same in all, being In Phaethon A. X Y, In Sula and Phalacrocorax A. X, In Fregata A, from which it may be inferred that Phaethon approaches the Cico-niidae and Fregata the Accipitres. They all possess the ambiens, caeca, a tufted oil-gland, and the four toes included in a web, which is but imperfectly developed in some. Sula and Phalacrocorax, with Plotus, form one family, Phaethon another, Fregata a third, and Pelecanus a fourth. 5. The Accipitres proper include the Falconidae and the true Vultures (between which there is not even any subfamily structural difference), together with the Strigidae. Their formula is A ; the ambiens is present (except in the Strigidae), as are caeca, a tuft to the oil-gland, and an aftershaft (except in Pandion). The order C H A R A D R I I F O R M E S , including all the Schizorhinal birds, is a large one, and may be divided into two cohorts-a. the Columba, and /3. the Limicola. They all, except Arctica alle, have two carotids. |