148 MR. F. E. BEDDARD ON THE SYRINX AND OTHER [Mar. 2, 
is of less extent, and there is an interval between it and the lung 
occupied by complete bronchial rings. 
In the paper referred to I have described the syringes of other 
genera of the Cuculide: in some genera (e.g. Cuculus) the syrinx 
is tracheo-bronchial; in others (e.g. Centropus) the syrinx presents 
a very close approximation in its structure to the bronchial syrinx of 
Crotophaga. In these Cuckoos the intrinsic muscles of the syrinx are, 
as in Crotophaga, attached a long way down the bronchus, but the 
bronchial rings anterior to the attachment of these muscles are not 
complete rings as in Crotophaga, but are very nearly so, inasmuch as 
their free extremities are separated by a very short extent of mem- 
brane, which widens out below the attachment of the syringeal 
muscles to form the membrana tympaniformis; there is, moreover, a 
similar change in the nature of the bronchial semirings at the point 
where the syringeal muscles are inserted. 
In the Caprimulgide there is a variation in the structure of the 
syrinx which is closely parallel to that of the Cuculide. 
Three types of syrinx can be recognized in this group, in the genera 
which I have myself been able to examine, which are: 
Caprimulgus. Batrachostomus. 
Chordeiles. Podargus. 
Nyctidromus. Steatornis. 
Aigotheles. 
In the first four genera the syrinx is tracheo-bronchial ; in Batra- 
chostomus and Podargus the syrinx approximates in structure to the 
purely bronchial syrinx of Steatornis. 
I need not redescribe the syringes of Caprimulgus and Chordeiles, 
which are already known from the investigations of Cuvier, Nitzsch, 
and Audubon. The remaining genus which possesses a tracheo- 
branchial syrinx, viz. Nyctidromus, has not, I believe, been described. 
In Nyetidromus (fig. 1) the syrinx is not widely dissimilar from 
that of Caprimulgus. The tracheal rings are separated mesially, both 
on the anterior and posterior aspect, by considerable membra- 
nous intervals; the last four are, however, closely applied, as 
shown in the accompanying drawing (fig. 1), which represents the 
syrinx viewed from in front; the terminal rings of the trachea are 
much more slender than the bronchial semirings, and the last appears 
to be defective laterally, or is covered by the succeeding first bron- 
chial semiring. The last two rings of the trachea, as well as the 
first five bronchial semirings, are ossified; the ossification has also 
extended on to the sixth bronchial semiring and the antepenultimate 
tracheal ring. The intrinsic muscles are attached on to the first 
bronchial semiring. Posteriorly is a rhomboidal ossified plate, to 
which the pessulus is attached ; it represents the middle portion of 
the last four or five tracheal rings, but is separated from them com- 
pletely. 
The syrinx of Zgotheles is displayed in the accompanying drawing 
(fig. 2). The syringeal muscles are inserted on to the third bron- 
