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Show 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 Cuculidae : 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 membrane, 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 Caprimulgidae there is a variation in the structure of the syrinx which is closely parallel to that of the Cuculidae. 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. AUgotheles. In the first four genera the syrinx is tracheo-bronchial; in Batrachostomus 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 Nyctidromus (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 membranous intervals; the last four are, however, closely applied, as shown in the accompanying drawing (fig. 1), which represents the syrinx viewed from in trout; 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 bronchial 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 completely. The syrinx of JZgotheles is displayed in the accompanying drawing (fig. 2). The syringeal muscles are inserted on to the third bron- |
