368 ON THE PETRELS COLLECTED DURING 



published in the ' Com ptes Kendus ' for that year *. The material for their 

 paper was obtained, I may remark, during the expedition of the French 

 ships ' Astrolabe ' and ' Zelee,' commonly known as the 'Voyage au Pole 

 Sud.' Basing their classification on the form and structure of the beak, 

 palate, and tongue, they divide up the group as follows : 



1. Borders of mandibles excavated by a longitudinal furrow dividing 

 them into inner and outer cutting surfaces. Tongue small, one-third 

 the length of beak, sagittate, posteriorly and laterally denticulate. 



Three genera Diomedea ; Puffinus, subdivided into Puffinus proper 

 (anglorum,obscurus,fuliginosus^, &c.) frndPriofinus (cinereus, cequinoctialis, 

 arcticus ?) ; and Thalassidroma (pelagica, leachii [= leucorrhoa'], oceanica, 

 fregetta \_=grattaria~], marina). 



2. Edges of upper mandible with transverse lamellae. Tongue as long 

 as the beak, large and thick, only free at the apex. 



One genus, Prion, divided into five subgenera Prion 5.5., Daption, 

 Falmarus, Ossifraga, and Priocella (for Priocella garnoti= TTialassoeca 

 glacialoides of this paper). 



3. Mandibles simple, with no double cutting-edges or transverse 

 lamellae, but with two slight, elongated " teeth " ; palate smooth or nearly 

 so; tongue of intermediate length. 



One genus, Procettaria, separated into two groups, one with the beak 

 quite short (nivea, desolata, brevirostris), the other with it long (antarctica, 

 lessoni, hcesitata, Forst. [?=Adamastor cinereus^). 



Zool. Chall. These points are illustrated in the atlas to the * Voyage au Pole Sud ' 

 pt. xi. p. 6. (pl- xxx ii-)> the classification adopted being explained in the text (vol. iii. 

 pp. 143-152) published some years later. 



The genus Pelecanoides is expressly excluded from the Petrels by these 

 authors, according to whom it is closely allied to the Little Auk (Alle 

 nigricans) of our northern seas. 



1849. Gray and Mitchell, in the * Genera of Birds ' f, make the Procel- 

 lariidae the fourth family of their Anseres. They are subdivided into the 

 Diomedeinae (of one genus) and the Procellariinae, of which latter five 

 genera are recognized (Prion, Pelecano'ides, Procellaria, Thalassidroma, 

 and Puffinus). The most characteristic generic characters of these are 

 figured on plate 178. 



1857. Bonaparte in his ' Conspectus ' $ gives a list of the then known 

 genera and species of the Procellariidae, which he divides into three sub- 

 families, Diomedeinse (Diomedea), Procellariinae, and Halodrominae. The 

 Procellariinse again are divided into five smaller groups, designated by 

 letters as follows : 



* Loc. cit. torn, xviii. pp. 353-358. 



t Loc. cit. iii. pp. 646-650. 



\ Conspectus generum avium, torn. ii. pp. 184-206. 



