Page 122. 
220 ON CERTAIN MUSCLES OF BIRDS. 
is always present, as are ceeca coli, an aftershaft, and a third pectoral 
muscle beneath the second; the oil-gland may be strongly tufted, or 
the tuft may be very weak; in the Megapodide it does not exist. The 
second pectoral is very long; and there is a characteristic shape about 
the sternum. In the Megapodide there is only one carotid, the left ; 
in all the others both are present. Neither Turnix nor Pterocles are 
included in this family. 
3. The Rallide, with State AB. XY, the ambiens and caca 
present, two carotids, an aftershaft, a tufted oil-gland, and a charac- 
teristic sternum. Parra is not included. 
4. The Otide, including the Otidinew, Gidicnemus, Serpentarius, 
and Cariama (and perhaps the next genus, Phenicopterus). The 
formula is B. X Y; the ambiens and ceca are -present, as is the after- 
shaft; there are generally two carotids, though in Otis denhami the 
right only is present, and in Tetraw the left; the oil-gland when 
present, as in all but Otis, is tufted, except in Cariama and Chunga. 
5. The Musophagide, with formula A B. X Y, an ambiens muscle, 
two carotids, an aftershaft, a tufted oil-gland, and no ceca. 
6. The Cuculide, with an ambiens muscle, two carotids, nude oil- 
gland, and ceca. They form two subfamilies :— 
The Centropodine, or Ground-Cuckoos, with formula A B. XY. 
The Cuculine, or true Cuckoos, with formula A. X Y. 
y. The cohort Psittaci presents in many points intermediate cha- 
racters between the homalogonatous and the anomalogonatous birds. 
With a constant formula A. X Y, no ceca or gall-bladder, an oil-gland 
tufted or absent, the ambiens may or may not be present, and the 
carotids may exhibit peculiarities in their arrangement.* 
The order ANSERIFORMES may be divided into two cohorts—«. the 
Anseres, 8. the Nasute. 
a. The Anseres include four families, (1) the Anatide, (2) the 
Spheniscide, (3) the Colymbide, and (4) the Podicipide. With the 
exception of the Podicipidew, they agree in having a formula A B. X, 
an ambiens muscle, ceca to the intestine (except Mergellus, in which 
there is only one small cecum), two carotids,a very elongate great 
pectoral muscle, which meets its fellow of the opposite side above the 
symphysis furcule in a median raphe, and a tufted oil-gland. The 
Podicipide have for formula B.X; the ambiens is absent, as is fre- 
quently the semimembranosus; the left carotid only is present ; there 
‘are ceca coli and a tufted oil-gland. 
6. The Nasute, 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 ceca, a tufted 
* See “ Proceedings of the Zoological Society,” 1873, p. 465. (Supra, p. 170.) 
