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 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 Caprimulgidte 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 : 



Oaprimulfftts. Batrachostomus. 



Chordeiles. Podargus. 



Nyctidromus. Steatornis. 

 ^gotheles. 



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- 

 brancliial syrinx, viz. Nyctidromus, has not, I believe, been described. 



In Nyctidromus (fig. 1) the syrinx is not widely dissinnlar 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 ill 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 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 riiomboidal 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 j^gotheles is displayed in the accompanying drawing 

 (fig. 2). The syringeal muscles are inserted on to the third bron- 



