1886.] POINTS IN THE ANATOMY OF CAPRIMULGIDZ. 151 
The intrinsic muscles of the syrinx are inserted on to the fifteenth 
or sixteenth bronchial ring, much lower down therefore than in 
Batrachostomus; the first two bronchial rings are complete; the 
following fourteen are semirings, but are wide, firmly united to each 
other, and ossified ; the membrana tympaniformis forms the inner 
wall of this and of the following section of the bronchus. The 
posterior section of each bronchus, as in Batrachostomus, is formed 
of slender cartilaginous semirings separated by wide membranous 
intervals. 
As far as the structure of the syrinx is concerned Steatornis stands 
alone; Podaryus and Batrachostomus are closely similar to each 
other, and are transitional between such genera as Caprimulgus and 
Steatornis ; the insertion of the intrinsic muscles so far down the 
bronchus, and the similarity between the anterior rings of the bron- 
chus and those of the trachea, is evidently an approach in structure 
to the bronchial syrinx of Steatornis. gotheles resembles Batra- 
chostomus more closely than it does Caprimulgus, but the number 
of bronchial semirings which intervene between the trachea and the 
insertion of the syringeal muscles is still further reduced. Capri- 
mulgus, Chordeiles, and Nyctidromus are very closely allied in the 
structure of their syrinx, which is tracheo-bronchial, and shows no 
approach to the bronchial syrinx of Steatornis, as do the syringes of 
Podargus, Batrachostomus, and (to a very much less extent) dgo- 
theles. 
The arrangement of the genera of Caprimulgide, as indicated 
above by the structure of their syrinx, is, I believe, in accord with 
the opinion of most ornithologists. With regard to other structural 
characters, the foliowing notes upon certain of the viscera and muscles 
appear to be worth recording. 
Visceral Anatomy. 
The intestines of the Caprimulgide are furnished with ceca, with 
the exception of those of gotheles. Mr. Forbes has left a MS. 
note to this effect, and I cannot find any trace of ceca in the spirit- 
preserved specimen of the last-mentioned form. In all the genera 
the left lobe of the liver is rather the smaller, and a gall-bladder is 
present save in Chordeiles’. 
The air-sacs in one specimen of Steatornis were rather peculiar 
in structure. The pcints in which they were found to differ from 
other birds are in the posterior intermediate air-sac. This sac 
on both sides of the body is considerably larger than the preceding 
anterior intermediate sac, and is furnished with two principal ostia 
placed near to the external border of the lung. These: pertures have 
a different position in relation to each other on either side of the 
body ; in the right lung these apertures do not both open into the 
posterior intermediate air-sac as they do on the left side of the body ; 
the most anterior of the two ostia opens into a small wedge-shaped atr- 
cell, which is completely separated by septa both from the posterior 
2 Garrod MS. 
