SPHENISCI 399 



pad at the commencement pf the membrana tympaniformis. 

 There is a tendency, as in the petrels, to the formation of a 

 bronchial syrinx. This is especially well seen in Aptenodytes 

 and Pygosceles. In the latter penguin the rings, three or 

 four of them, after the bifurcation preserve the character of 

 the tracheal rings, being deeper than those which follow, 

 and being at the same time complete rings. 



In the penguin's sJcull the sutures are not so completely 

 closed as in most birds ; in this they resemble the ratites 

 among existing birds. 



In Eudyptes chrysocome, which may be taken as a type 

 of the Sphenisci, the skull is schizognathous ; the maxillo- 

 palatines are thin plates which are curved backwards, as in 

 many Passeres and in some other schizognathous birds ; but, 

 instead of being flatter upon the ventral and dorsal surfaces, 

 they are compressed laterally. These hones gently nip the 

 vomer, which is also composed of two flattened rami partially 

 separated up to nearly the very anterior end. The palatines 

 are large and flat with' a very slightly developed internal 

 lamina ; they nearly come into contact in the middle line. 

 The pterygoids are unique among birds for their relatively 

 immense size ; their shape is almost that of the human 

 scapula, the wider region being at their junction with the 

 palatines. Each pterygoid is perforated at the middle of 

 the wider part. The nostrils are holorhinal, and the nasal 

 bones at their posterior extremity are seen to overlap the 

 f rentals. There are strongly .marked impressions for the 

 supra-orbital glands. The lacrymals reach the jugals, where 

 they expand into a flattened foot ; the descending limb of 

 each lacrymal, which is flattened out in a plane parallel with 

 the long axis of the skull, is there perforated by a very large 

 foramen. It is extraordinary that in this bone, as in the 

 maxillo-palatines, the plane of the bone is in a different 

 direction from that of the same bones in other birds. There 

 are no ossified ectethmoids. On either side of the foramen 

 magnum are occipital fontanelles of small size. The inter- 

 orbital septum is largely vacuolate posteriorly, In front of 

 the occipital condyle, in the region occupied by the basi- 



