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Show 174 MR. F. E. BEDDARD ON THE CUCKOOS. [Feb. 17, the remaining bronchial semirings are not closely united, but separated by considerable membranous intervals. Impressed by the difficulty of detecting the true nature of the syrinx in Guira pirigua, I carefully reexamined Phcenicophaes and Eudynamis to prevent a possible error in the statement just made concerning the syrinx of these two genera, but I was unable to see that the syrinx was other than tracheo-bronchial as in Cuculus, Piaya, &c. Coua ruficeps.-The following description of the syrinx of this Cuckoo is compiled from sketches made by Prof. Garrod. It appears to resemble in all essentials the syrinx of Centropus, Pyrrhocentor, &c. ; the first seven bronchial semirings are more or less firmly united, and their inner extremities are separated by a narrow membranous interval ; the intrinsic muscles of the syrinx are attached to the seventh bronchial semiring ; the remaining semirings are not so complete as the anterior ones, and the extent of the membrane uniting their inner extremities is therefore wider and forms the membrana tympaniformis. Pterylosis.-The fact that the various genera of Cuckoos differ in the arrangement of the feather-tracts was first pointed out by Nitzsch. He distinguished three groups : in the first "the pectoral portion of the inferior tract is dilated, uniformly sparsely feathered, and extended over the whole breast;" to this group belong Cuculus and Eudynamis. In the second group, " the pectoral portion of the inferior tract is not quite so broad but more densely feathered, and encloses posteriorly a narrow insular space ; " this group contained the genera Scythrops, Centropus, Crotophaga, Saurothera, &c. Finally, the Phcenicophainse are characterized thus : - " The dilated pectoral part of the inferior tract is narrow and of uniform breadth, and encloses no space." I do not find, however, that Nitzsch's account applies altogether to the specimens that I have studied, though he is undoubtedly right in calling attention to the considerable differences that are found in the arrangement of the feather-tracts in this family. Before indicating what appear to me to be the classificatory results that may be obtained from a study of the pterylosis of the Cuculidee, it will be best to describe the genera separately. Cuculus canorus.-Nitzsch's description of the pterylosis of this Cuckoo appears to me to be for the most part correct ; I recapitulate it here for the purposes of an easier comparison with the other types. The feathering on the throat completely occupies the inter-mandibular space, the feathers are more closely placed anteriorly and become more sparsely distributed posteriorly. The ventral tract is very soon separated into its two halves, in each of which the feathers are arranged in parallel lines inclined at an oblique angle to either axis of the neck. Over the sternum the pectoral tract is very wide, becoming gradually narrower posteriorly until it terminates in a single row of feathers some way in front of the anus. There is no indication of any division of the ventral tract such as is characteristic |
