Page 118. 
216 ON CERTAIN MUSCLES OF BIRDS. 
Subfamily 1. Coraciine. 
3g 2. Momotine. 
Mf 3. Todine (?). 
Order III. CYPSELIFORMES. 
Family Macrocuires. 
Subfamily 1. Cypseline. 
# 2. Trochiline. 
There are peculiarities in the arrangement of the ceca of the intes- 
tine and of the tuft of feathers on the oil-gland which are correlatable 
with this presence or absence of the ambiens muscle. Some birds 
possess czeca to the intestine at the same time that the oil-gland is 
tufted (1) ; others have ceca and a nude oil-gland (2), others a tufted 
oil-gland and no ceca (3), whilst a few have no ceca and a nude oil- 
gland (4); the genera, Didunculus, Goura and Treron, amongst the 
Columbe, have no ceca and no oil-gland, wherein they differ from all 
_ other birds. Now it is a curious fact that it is only amongst the 
homalogonatous birds that the first of the above-named conditions is 
found, namely a tufted oil-gland combined with ceca to the intestine ; 
and what is more, they nearly all agree with it. The following table 
(II.) contains the names of those birds in which a tufted oil-gland is 
combined with ceca to the intestine, an asterisk indicating the families 
in which there are certain exceptions. 
TaBE II. 
Struthiones*. Gruide. 
Orypturt. Anatide. ° 
Galline*. Spheniscide. 
Otide*. Colymbide. 
Phenicopteride. . Procellariide*. 
Palamedeide. Ciconiide, 
Rallide. Ardeide (one cecum). 
Liimicole. Steganopodes. 
Laride. Falconide. 
Alcide. Vulturide. 
Respecting the exceptions, it may be mentioned that the Siru- 
thiones and Otis have no oil-gland; but as in their nearest allies it is 
tufted, they may be included amongst those in which it is so also. 
Amongst the Galline I have always found the oil-gland nude in the 
Megapodide (Talegalla and Megacephalon). The Storm-Petrels have 
no cxca, and the Ardeide have only one. 
It is therefore evident that from the whole list of birds termed 
homalogonatous, only the Musophagide, Psittaci, Columbe, Ouculide, 
