OSTEOLOGY OF THE PENGUINS. 395 



behind; and there may be a minute foramen in front. The 

 hinder moieties of the palatine bones are very broad and 

 parallelogrammatic in outline, their mesial and inner margins 

 being nearly parallel to each other. Passing forwards, they 

 gradually rise and contract, to merge finally anteriorly with 

 the interraaxillaries ; the sutural traces of the articulations 

 being plainly evident in Aptoiodytes (and in Pygosceles, Watson), 

 but entirely obliterated in Eiidyijtes and Spheniscus. 



The vomer is profoundly cleft posteriorly, the long slender 

 limbs being weakly coalesced with the palatines ; in front it is 

 a free, vertical lamina of bone, sharp at the apex, and projecting 

 without contact into the inter-maxillo-palatine space. Either 

 maxillo-palatine is of a subcaucellous structure, elongated and 

 narrow, directed backwards as a free process. This much for 

 Aytenodytes, while in Spheniscus demersus the osseous structure 

 is far more compact, and the form of either maxillo-palatine 

 more lamellar. 



There are no basi-pferygoid processes, and the hasi-sphenoidal ros- 

 trum is flat upon its under side ; narrow, rounded ofi'in front in A. 

 pennantii, but in Endyptes extended on as a small pointed spine. 



One of the features in the skulls of Penguins is the difference 

 in the curving of the ' infraorbital bar,' and of this Watson 

 has said : " In respect of the form and curvature of the zygo- 

 matic arch, the skulls of Pygosceles and of Aptoiodytes agree 

 with that of Eudyptes, and differ from that of Sjjhejiiscus." This 

 fact is again referred to here, as the form assumed by the 

 mandible in the several genera varies, and is so peculiar that 

 it offers another very good diagnostic character for them. 



In AiJtenodytes, the depth vertically of either ramus from 

 junction of middle and posterior third, gradually tapers away 

 to the mandibular apex. In Pygosceles the middle third of 

 either ramus is evidently deeper than it is elsewhere ; this is 

 still better marked in Sp)hemscus, and reaches its maximum, 

 where it is conspicuously pronounced, in Eudyptes chrysocome, 

 and still more so in E. chrijsolophus. Upon the whole, the lower 

 jaw is V-shaped, with a very small, weak symphysis in all the 

 short-billed Penguins, and not much improved in this particular 

 in the long-billed ones. It is composed of the usual elements 

 found in the mandibles of birds generally, and often the sutural 



