160 MK. P. E. BEDDARD ON THE [June 16, 



united to the pessulus. Posteriorly the pessukis 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 JVisaettcs. 



Genus POLYBOROIDES. 



I found, much to my surprise, that the syrinx of P. typicus is 

 not like that of Polyhorus, that it does not conform to the 

 Falconine, but to the Aquiline, or Buteonine, type. 



The bronchial rings are close together, and there is no spacious 

 membrana typaniformis externa as in Polyho^nis 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 Polyhorus in the ' List of 

 Yertebrated Animals ' *. 



Genus VuLTUE. 



The two species, Y. cvtiricularis 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 fibi'es 

 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 papillae upon the tongue diflfer in the two species. 



