286 MR. W. K. PARKER ON THE OSTEOLOGY OF BALyENICEPS REX. 



cellaridce, e.g. the Short-tailed Petrel (Puffinus brevicauda) , from Green Island, Bass's 

 Straits (1224, Osteol. Cat. Mus. Coll. Chir. vol. i. p. 230). 



Group 5. — Fronto-maxillary hinge more or less moveable and splint-like ; palato- 

 pterygoid joints freely gliding on a more or less synovial 'rostrum'; ento-pterapophysis 

 longer and more delicate, as is its answering apophysis on the pterygoid ; the facets 

 of this little apophysis are rather round than oval, and their position more backward, 

 being midway between the palatine and os quadratum ; in this group the vomer is 

 often well developed and cellular. 

 Examples : — 



Strix, Ulu/a, Asia, Bubo (Owls). Charadrius hiaticula (Ring Dotterel). 



Columha, Palumbus, Treron chlorogaater, Scolopax (Snipes and Woodcocks). 

 Goura victorias, Geophaps smithii (the typi- Liinosa melamira (Godwit). 

 cal Pigeons). Numenms arquata (Curlew). 



Vanellus cristatus (Lapwing). Tringa variabilis (Sandpiper). 



Group 6. — No movement of the facial on the cranial sclerotomes, the differentiation of 

 the ethmoid and pre-sphenoid in the cranio-facial axis being soon obliterated by the 

 fusion from below upwards of these vertical centrums. The rostrum is large, and the 

 ento-pterapophyses unusually well developed ; but they are not connected with the 

 anterior part of their own haemal bones, the pterygoids, as in Fowls and Geese, nor with 

 the middle, as in Owls, Pigeons, and Snipes, but articulate with a facet on the distal 

 end of these bones, which are wedged in between the ento-pterapophyses and the 

 quadrate bones. 



In these non-typical birds the pre-maxillaries are relatively small and feeble (as the 

 rule), the maxiliaries unusually large, and lying in the same plane as the pre- 

 maxillaries ; the palatals small, and pushed aside (so as to resemble the ' transverse 

 bones ' or ' ecto-pterygoids ' of the Crocodile) by the unusual development of the 

 vomer, which, thin, broad, and split at both ends, passes backwards to articulate with 

 the pterygoids. These latter bones are not at all bird-like, but have taken on much of 

 the laminar character of their homologues in the Reptilia, and are adapted to the 

 vomer by a squamous suture, whereas in typical birds they articulate with the palatines 

 by a synovial joint. 



Example : — Struthionidee (the Ostrich family). 



Orbito- sphenoid. (PI. LXV. fig. 1, os.) 

 Looking at tlie middle part of the well-formed orbital roof of Balseniceps towards 

 the axis, we see a small foramen two lines above the oval membranous space already 

 mentioned as a landmark between the ali- and orbito-sphenoids. This small foramen 

 pierces the sphenoido-frontal just above its union with the diverging plate of the orbito- 

 sphenoid. Five lines in front of and a little above this passage is another, scarcely 



