REPORT ON THE ANATOMY OF THE PETRELS. 19 
Petrel in which the beak is fringed in a way similiar to that here described is Halobena 
cerulea, of which, however, as yet I have been unable to examine more than skins. 
The existence of a peculiar fringe of lamellz along the margin of the mouth has often 
been insisted on as an argument for placing Phanicopterus amongst the Lamellirostres, but 
the development of, at least, a very similar arrangement in Prion and Halobena, 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 
CEstrelata, 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 Aetpetes and Thalassaca 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 Diomedeine 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 exulans, 
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 Oceanitide, (vide fig. 5, Oceanites), and the genera Cymochorea (fig. 9), Pro- 
cellaria, and Halocyptena of the Procellariide, 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 papillz. This is the form of tongue found, more or less modified, through 
the entire group. 
In Gstrelata (fig. 15),! Majaqueus, Bulweria, and Puffinus obscurus the tongue 
1] 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 “ Cstrelata brevirostris,” but does not agree with the other species of that genus 
