1873.] DR. J. E. GRAY ON THE GENUS OCADIA. 191 



Male with tuft of white feathers : length 4f in., bill f in., wing 

 3 in., tail lg in. 



Male with tuft of reddish feathers : length A\ in., wing 3| in., 

 tail 1-J in., bill | in. 



This latter is a young bird certainly ; but the curious part is that 

 it has the luminous portion of the back nearly perfect, whereas in 

 the others the tuft of white feathers is always perfect before the 

 luminous feathers on the back ; the tail-feathers are also differently 

 coloured, in this bird being of a greenish brown, whilst in that with 

 the white feathers it is of a reddish-brown colour. 



P.S. November 20th. — Very few of these birds are now seen ; they 

 are evidently leaving for some other locality. Bill black ; the sides of 

 lower mandible marked with streaks of light yellowish brown ; eye, 

 legs, toes, and claws black. 



15. Helianthea osculans, Gould, P. Z. S. 1871, p. 503. 

 Length 5f| in., bill 1| in., wing 3 in., tail 2 in. 



16. Metallura smaragdinicollis, Lafr. et D'Orb. 



This is rather a common bird here ; and I have also one nest and 

 eggs. The nest was built in a deserted Indian hut, and suspended to 

 the roof inside by long grass. 



17- Metallura ^neicauda, Gould. 



Length 4| in., bill l\% in., wing 2| in., tail 1| in. This species 

 has no throat-mark ; but the tail is unusually beautiful, especially on 

 the underside. Bill black ; eye, legs, toes, and claws black. I 

 found it feeding off small purple flowers. The stomach contained 

 the remains of small insects. 



8. On the Genus Ocadia. By Dr. J. E. Gray, F.R.S. &c. 



[Received December 23, 1872.] 



I have lately had one of the duplicate specimens in the British 

 Museum of this species formed into a skeleton, and thus had an 

 opportunity of examining its skull, which proves that it should be 

 referred to Bntaguridee, as I was prepared to expect from the exami- 

 nation of a finely grown shell, from the contraction of its cavity on the 

 sides of the front and back opening, which, as in Batagur, contracts 

 rather more than it does in Emydidce. This proves most distinctly 

 the importance of the examination of the skulls of these animals, and 

 that their study is necessary for the disposition and determination of 

 the species of the other families, as well as of Trionychidte. 



The alveolar surface of the upper jaw is broad throughout the whole 

 of its length, with a central and internal marginal ridge, which extends 

 along the whole length of the alveoli, the middle or inner ones being 

 separated in front by a central oblong longitudinal cavity. The 

 marginal ones are united in the centre. The alveolar surface of the 

 lower jaw is deeply concave, with a highly raised ridge on the outer 



