222 ON CERTAIN MUSCLES OF BIRDS. 
2. The Laride, with A. X Y formula, and an ambiens muscle. 
3. The Gruide, with formula A B. X Y, and ambiens muscle. 
4. The Alcide, with formula A B.X, and no ambiens muscle. 
The AnomaLogonatous birds form three cohorts—«. the Passeri- 
formes, B. the Piciformes, and y. the Oypseliformes. They are divisible 
into the following families :— 
a. Passeriformes. 
1. The Passeres, with a formula A.X Y (except in Dicrwrus, in 
which it is A.X), a characteristic palate and sternum (except in 
Piteroptochus), a left carotid only, and a characteristic tensor patagii 
brevis muscle (to be described on a future occasion). 
2. The Bucconide, of which I have not dissected any example, but 
which most probably come here. 
3. The Trogonide, with formula A. X, a left carotid only; and a 
very passerine pterylosis. 
4, The Meropide, with a formula A. X Y, and a left carotid only. 
5. The Caprimulgide, with a formula A. X Y, and two carotids. 
6. The Steatornithide, with a formula X Y, and two carotids. 
7. The Coractide, in which the Coractine and Momotine are com- 
bined, on account of their not presenting family differences. They 
have a formula A. X Y, and two carotids. 
8. The Galbulide, with a formula A. X Y or A. X, two carotid 
arteries, and a scansorial foot. 
B. Piciformes. 
1. The Picarie, to include the Pici, the Ramphastide, and Oa- 
pitonide, these three not in any point presenting family differences. 
They may be divided into two subfamilies, the Pici forming the one, 
the Ramphastide together with the Capitonide forming another. The 
formula is A. X Y (except in the Picine among the Pici) ; the form of 
the sternum and of the tensor patagii brevis is characteristic. The 
foot is scansorial. 
2. The Upupide, with formula A. XY, a chetacteristic pterylosis, 
a left carotid only, and a passeriform foot. 
3. The Bucerotide, with formula A. X Y, no fat found on the body, 
a characteristic sternum, and one or two carotids. 
4. The Alcedinide, with formula A. X, and two carotids. 
y. Oypseliformes, including the Cypselide and Trochilide, between 
which the differences are only of subfamily importance. The 
formula is A; the tensor patagii brevis and the pterylosis are charac- 
teristic, as is the sternum; and there is only a left carotid (except in 
Cypseloides). 
