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Show 158 MR. F. E. BEDDARD ON THE [June 16, ness or incompleteness of the bronchidesmus is a feature which apparently differs from species to species. In F. feldeggi I find that the membrane is incomplete, that is to say it does not extend right up to the bifurcation of the bronchi. In F. sacer and F. biarmicus, on the other hand, the bronchidesmus is quite complete. Upon other species I a m unable to report. Genus HIERACIDEA. This genus, represented for m e by the species H. berigora alone, has a syrinx belonging quite to the same type as that of Falco. In fact a general description would apply equally well to both, an obvious justification of the close alliance usually asserted to exist between them *. Genus MILVAGO. This genus, as represented by Milvago chimango (text-fig. 16) and M. chimachima, is essentially Falconine in the characters of its syrinx, and does not appear to m e to come nearer to Polyborus than to Falco. Text-fig. 16. Syrinx of Milvago chimango, lateral view. X 2. The first bronchial ring is very thick, especially posteriorly, where it curves down and bends forward; it is to this piece that the intrinsic muscles are mainly attached, though they are also inserted into the membrana tympaniformis externa. It is, I take it, the homologue of the thickening of the membrana tympaniformis which is so characteristic of Falco. Genus HERPETOTHERES. Herpetotheres cachinnans has a syrinx which is constructed upon the Falconine plan. * I may remark, however, that the backwardly directed papillae upon the tongue are shorter than in any Falco. |