THE BIEDS OF AUSTRALIA. 
species have the strong and fully webbed feet of the Sea-Terns.” Twenty 
years afterwards in the monograph in the Cat. Birds Brit. Mus., Vol. XXV., 
Saunders had so revised his views that no fewer than eleven genera were 
there included : viz. Hydrochelidon, PhcetTiusay Gelochelidon, Hydroprogne^ 
Seena, Sterna, Ncenia, Procelsterna, Anous, Micranous and Gygis. The most 
peculiar feature in this treatment is, that under Sterna are lumped forms much 
more diverse than some of those allowed as distinct. Thus the differences 
between Anous and Micranous (a genus introduced by Saunders himself) 
seem lighter than those between the two Sooty Terns of which Saunders 
wrote, and the young are so ahke that Saunders himseK confused them. Since 
the Cat. Birds Brit. Mus., these birds do not appear to have been treated as 
a whole, but in the A.O.U. Checklist, 3rd ed., 1910, where no reasons are given, 
I find the following system accepted : four genera, Gelochelidon, Sterna, Hydro- 
chelidon, and Anous ; while the genus Sterna is subdivided into five subgenera : 
Sterna, Thalasseus, Actochelidon, Sternula, and Onychoprion. The only 
difference between this and Saunders’s treatment is, that the Caspian Tern 
is only admitted as possessing characters of subgeneric value under Sterna 
in the A.O.U. Checklist, while Saunders acknowledged it to differ generically, 
the former using the name Thalasseus, and the latter Hydroprogne. 
The diversity between the treatment of genera and subgenera by the 
American and British ornithologists is well seen in the Hand-List of British Birds 
just published, which bears the names as joint authors, E. Hartert, F. C. R. 
Jourdain, N. F. Ticehurst, and H. F. Witherby. It is acknowledged that 
Dr. Hartert is mainly responsible for the nomenclature, but that all have 
discussed the points. Therein subgenera are entirely rejected, and apparently 
Saunders’s 1876 disposition absolutely followed, the later 1896 revision 
being disagreed with. The difficulty with this acceptance is well pointed out 
by Saunders in the sentences quoted above, viz. the recognition of the “ very 
natural genus ” Hydrochelidon with very little, if any, better features for 
separation than exist between Gelochelidon and Sterna ; while the inclusion 
of S. caspia (= tschegrava) as a member of the genus Sterna in the A.O.U. 
Checklist, though Gelochelidon is separated, seems just as arbitrary. The 
most reasonable method, though admittedly imperfect, seems the recognition 
of various well-defined groups which may be considered as of equal value, 
whatever value may be allowed them ; and in this place I propose to use 
names generically which are more commonly considered subgenera. It should 
be remembered that generic names are matters of convenience only, and are 
used to indicate relationships ; and if by means of them we can more clearly fix 
distinctions, we should use such means. To particularise : we have the Sooty 
Tern ; this constitutes a group separated from the majority of Terns by 
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