174 MR. F. E. BEDDARD ON THE CUCKOOS, [Feb. 17, 



the remaining bronchial semirings are not closely united, but sepa- 

 rated 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, imiformly 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 fouud 

 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 Cuculidae, 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 



