. The structure and classification of birds . est seventy-eight rings of thetrachea are modified through being thinner than those else-where, and this portion of the tube is of a greater calibre thanthat above. In Cicoina alba the lowest twenty-nine rings arethus changed in structure, and there is a small prolongationupwards of the lateral portions of the three lowermosttracheal rings, which forms a consolidated triangular processon each side, overlapping the next few rings and lookingextremely like the rudiment of the similarly situated proces-sus vocales of the passerinetracheophone syrinx,
. The structure and classification of birds . est seventy-eight rings of thetrachea are modified through being thinner than those else-where, and this portion of the tube is of a greater calibre thanthat above. In Cicoina alba the lowest twenty-nine rings arethus changed in structure, and there is a small prolongationupwards of the lateral portions of the three lowermosttracheal rings, which forms a consolidated triangular processon each side, overlapping the next few rings and lookingextremely like the rudiment of the similarly situated proces-sus vocales of the passerinetracheophone syrinx, whichresemblance is increased bythe thinness of the neigh-aiid by theirfrom beforebackwards. The bronchial syrinx isseen in its most extreme de-velopment in Steatornis andin Crotophaga, where it wasoriginally described by MUL-LER ; but other cuckoos andgoatsuckers, as has beenshown by me,1 possess alsoa syrinx which may becalled bronchial; further-more, as WUNDEELICH hasshown,2 the owrl tribe resem-ble the goatsuckers in this being flattened. FIG. 48.—SYRINX OF Steatornis. FRONTVIEW. (AFTER GARROD). respect, while there are in-dications of the bronchial syrinx in certain petrels. The fullest description of the syrinx of Steatornis, whichwe take as a type of the perfectly formed bronchial syrinx, 1 On the Syrinx and other Points in the Anatomy of the Gaprimulgidse,P. Z. ,S. 1886, p. 147; On the Structural Characters and Classification of theCuckoos, P. Z. S. 1888, p. 168. - Beitriige zur vergleichenden Anatomie und Entwickelungsgeschichte desunteren Kehlkopfs der Vf^el, Nor. Act. Acad. Leop. Cces. 1884. 70 STRUCTURE AND CLASSIFICATION OF BIRDS is contained in a paper upon the general anatomy of thisbird by From that paper we borrow the descrip-tion as well as the illustration. It will be seen from thatdrawing (fig. 48) that the trachea of the bird bifurcates, asdoes the trachea of a mammal, without any modification ofthe rings, either tracheal or bronchial. The latter
Size: 1225px × 2040px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade1890, booksubjectbirds, bookyear1898
