84 MK, -W. p. PTCRAFT ON THE (Teb. 1 5, 



siclerable size ; and in Phalacrocorax, Plotus, and Pelecamis. 

 Amongst these it is of moderate size onl_y in Phalacrocorax carlo ; in 

 the other forms it varies, occurring in ahnost every gradation down 

 to a minute aperture. In Plotus anhinr/a it appears to be wanting 

 altogether. Outside the group it occurs in the Ciconia', Procellario', 

 and Splienisci, &c. 



The maxillo-palatine processes differ — in the adult at least — 

 from the other 8teganopodes, and resemble rather those of the 

 Ibises and Herons, in that thej^ only extend horizontally, and 

 only slightly vertically. They are completely fused throughout 

 the greater part of their extent, but send backwards, into the 

 lachrymo-nasal fossa, two free spongy masses. The nearest 

 approach, as previously hinted, to this arrangement is found in 

 the Ibises and Herons. 



Whilst in all the other Steganopodes the palatines are more or 

 less completely fused posteriorly, in PJiaetJion they are quite free, 

 and in Fregata nearly so. 



A vomer occurs only in Phai'tJion and Fregata. In the former 

 it is cleft posteriorly ; in both, in the adult, it is completely fused 

 posteriorly with the palatines. In Phaethon it is somewhat " knife- 

 blade-shaped," and received between the ends of tlie maxillo- 

 palatine processes. The dorsal edges of the cleft posterior ends 

 are closely applied to the basisphenoidal rostrum. A bicarinate 

 vomer is fouud also in the Herons. The vomer is fused with 

 the palatines posteriorly, outside the Steganopodes, in all the 

 other Ciconiiformes, the Anseriformes, Procellariiformes, and 

 Sphenisciformes. 



The anterior nares are large, and pervious, in which respect 

 they resemble also those of the Pelicans. 



The skull of a nestling Phaethon, prepared under my direction, 

 revealed some very instructive facts, which will be best understood by 

 a reference to the figures (Pl.VIII. fig. !«)• That of the ventral view 

 of the skull shows that at this stage the palate is schizognathous. 

 The maxillo-palatine processes are small, triradiate, perfectly 

 separate in the middle line, and do not give the sliglitest promise 

 of the "spongy" nature which they afterwards acquire, when 

 they have fused one with another, to form the desmognathous 

 palate. The aperture of the anterior nares, again, is mucb larger, 

 and extends farther backwards than in the adult, so much so 

 indeed as nearly to convert the holorhinal into schizorhinal nares. 

 The nasal hinge, so strongly marked a feature in the adult skull, is 

 here conspicuous by its absence. A second skull, somewhat older 

 than this, shows stages intermediate between this and that of the 

 adult. 



The skulls of the adult Pelecamis and Phaethon do not appear to 

 possess much in common, except the form of the basitemporal 

 plate ; but this point is, I think, a rather important one. 



The maxillo-palatine processes in Peleeanus very closely 

 resemble those of the Ciconicp. They consist of delicately cancel- 

 lated tissue of considerable vertical extent, extending the whole 



