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Show 160 MR. F. E. BEDDARD ON THE [June 16, united to the pessulus. Posteriorly the pessulus is fused with the ring in front of that from which it originates anteriorly. Genus SPIZAETUS. The syrinx of S. ceylonensis presents no differences from that of S. orientalis, and the genus itself should, I think, be placed near to Nisaetus by virtue of its syringeal characters. There is, however, a complete union between the rings which are connected with the pessulus, although the intrinsic muscles are inserted on to a semiring which appears to correspond exactly to that which bears the same muscles in Nisaetus. Genus POLYBOROIDES. I found, much to my surprise, that the syrinx of P. tyjricus is not like that of Polyborus, that it does not conform to the Falconine, but to the Aquiline, or Buteonine, type. The bronchial lings are close together, and there is no spacious membrana typaniformis externa as in Polyborus and Falco. I find also that the intrinsic muscles are attached to the second bronchial semiring. The name of this genus is clearly unfortunate, as is its association with Milvago and Polyborus in the ' List of Vertebrated Animals'*. Genus VULTUR. The two species, V. auricularis and V. calvus, which I have examined, show rather more differences than might perhaps have been expected. The differences concern the musculature of the organ t. In V. auricularis the muscles are inserted upon the second bronchial semiring; in V. ccdvus the bulk of the fibres are inserted upon the same ring, but a good many bundles of fibres stray down a few rings beyond. Except for the fact that the connections of the pessulus are " normal," the syrinx agrees in structure with that of Gyps. It is moreover cartilaginous, the pessulus alone being bony. Genus GYPS. The syrinx of Gyps rueppelli shows one characteristic feature which I have not observed in any other Accipitrine bird. The pessulus, or threeway-piece, is not coossified posteriorly with any of the tracheal rings. It is only connected by membrane, and forms therefore a movable triangular plate, which (in the spirit-preserved specimen at any rate) is depressed below the level of the tracheal rings which abut upon it-thus giving a peculiar and unusual appearance. The pessulus itself is ossified, the rings of the trachea and bronchi are cartilaginous. The intrinsic muscles * List of the Vertebrated Animals now or lately living in the Gardens of the Zoological Society of London, 9th ed. 1896, p. 403. t The horny papillaa upon the tongue differ in the two species. |