REPORT ON THE ANATOMY OF THE PETRELS. 19 



Petrel in which the beak is fringed in a way similiarto that here described is Halohcena 

 carulea, of which, however, as yet I have been unable to examine more than skins. 



The existence of a peculiar fringe of lamellae along the margin of the mouth has often 

 been insisted on as an argument for placing Phcenicopterits amongst the Lamellirostres, but 

 the development of, at least, a very similar arrangement in Prion and Halohcena, birds of 

 a very different group again, ought to show that an adaptive contrivance of this kind 

 may be, apparently, independently developed without great difficulty and yet with many 

 features of common resemblance, in different birds without necessitating any immediate 

 genetic connection between its possessors. 



In Fulmarus (PI. II. fig. 22) a rudimentary fringe of the upper mandible is present, 

 a little more developed than in Daption ; in other respects it conforms to the type of 

 (Estrelata, the spines, however, being very small and rudimentary. Ossifraga is similar 

 in all essential points, but the palate is longer, and, at least in young birds, more spinu- 

 lose. In Aeipetes and TJialassmca the pectination of the mandible can only just be 

 traced ; the palate is much longer and narrower in shape than in Fulmarus, the spines 

 smaller, and the palatine ridges better marked. 



In Pelecanoides (PI. II. fig. 20) the palate is quite smooth throughout, with no ridges 

 or spines, except on the area round the posterior nares, which is pretty uniformly 

 covered with sharp elongated spines of fair size. 



In the Diomedeinse the palate is comparatively smooth. There is a long prenarial 

 ridge, only with slight indications of spines at its most posterior part. The spines 

 bounding the narial and Eustachian apertures are well-marked, those on the palate 

 small and best developed towards the posterior end of the prominent palatine ridges. 

 Between the latter and the median fissure are developed, especially in Diomedea exidans, 

 additional spines of small size, as well as a short row outside their most posterior part. 

 Outside the tongue, between it and the inner margin of the jaws, the mucous membrane 

 of the floor of the mouth has on each side a well developed series of stronger spines. 



The tongue, as may be seen by a glance at Plate II., where the chief variations of its 

 form are represented, is by no means constant in shape in the Tubinares. 



In the Oceanitidse, (vide fig. 5, Oceanites), and the genera Cymochorea (fig. 9), Pro- 

 cellaria, and Halocyptena of the Procellariidse, the tongue is of triangular shape, fairly 

 fleshy basally, but tapering and becoming thinner anteriorly, its extremity being pointed 

 and more or less membranous, so as to easily be destroyed by rough usage. Its 

 posterior margin, or base, is somewhat concave, and fringed by a row of small retro- 

 verted pointed papillae. This is the form of tongue found, more or less modified, through 

 the entire group. 



In (Estrelata (fig. 15), 1 Majaqueus, Bulweria, and Puffinus obscurus the tongue 



1 I have figured (fig. 16) on Plate II. a tongue of different form from any other known to me as occurring in the 

 group of Petrels. It has been labelled " (Estrelata brevirostris," but does not agree with the other species of that genus 



