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Show 170 MR. F. E. BEDDARD ON THE CUCKOOS. [Feb. 17, Edwards' has a gall-bladder ; I have failed to find one in Eudynamis Seeing that the gall-bladder is occasionally absent and occasionally present in the same genus (Centropus), it does not appear to me to be advisable to make use of it as a systematic character. The variations exhibited in the tendons of the patagium are very inconspicuous ; the general disposition of the tendon of the tensor patagii brevis has been described by Garrod 2 ; the only genus which at all departs from this is Geococcyx, in which the tendon of the tensor patagii brevis sends off a short branch forwards attached to the extensor metacarpi radialis a little way in front of the attachment of the main part of the tendon. The number of rectrices is not, as Nitzsch has stated, constantly 10 ; in Guira and Crotophaga this number is reduced to 8. This is another reason in addition to those stated below for associating together these two genera. Muscles of the Thigh.-Mr. Garrod has proposed to divide the Cuculidae into two subfamilies according to whether they possess or lack the accessory femoro-caudal muscle ; the muscle-formula of one group, the Centropodina, is therefore A B X Y ; that of the second subfamily, the Cuculina, A X Y ; adding to his list those species subsequently dissected by himself and also by Mr. Forbes and by myself, I find the following arrangement:- CENTROPODINA, A BXY. CUCULINJE, A X Y. Centropusphasianus. Cuculus canorus. Geococcyx affinis. Coccyzus americanus. Geococcyx sp. Piaya cayana. Crotophaga ani. Cacomantis sepulchralis. Pyrrhocentor celebensis. Saurothera dominicensis. Rhinococcyx curvirostris. Saurothera vielloti. Guira pirigua. Diplopterus navius. Phanicophaes sp. Eudynamis taitensis. Eudynamis orientalis. Syrinx.-So far as I have had the opportunity of studying the structure of the syrinx in the Cuckoos, this organ appears to present two chief modifications : - (1) the ordinary tracheo-bronchial syrinx as in Cuculus ; (2) the bronchial syrinx, which has been long known as characteristic of Crotophaga, but which also distinguishes a number of other genera. In the following brief description of the syrinx in the several genera only the more essential points have been indicated. Cuculus canorus.-The syrinx is tracheo-bronchial ; the tracheal and first bronchial rings are largely ossified ; the anterior tracheal rings are of uniform width throughout; the posterior rings, as in Steatornis 3 and other birds, alternately overlap each other, and so 1 Histoire Nat. de Madagascar, Texte i. le partie, p. 174. 2 Loc. cit. p. 360. 3 Cf. Garrod, Coll. Papers, p. 184. |