LARIFORMES. 
America and included six genera. As far as I can judge, Coues’s idea of generic 
groups approximated very closely to those held by American systematists of the 
present time, though subgenera are more commonly used just at this present 
than formerly ; hut the recognition of these seems to be on the decrease, the 
practice to use only one term, and that of generic value, apparently coming 
into stronger favour, as is acknowledged in the preface to the third edition 
of the Checiclist of North Ainerican Birds ^ p. 9 : “ Many changes in generic 
names have resulted from raising to generic rank various groups recognised 
merely as subgenera in the first and second editions of the Checiclist^ their 
reduction in grade by the original Committee having failed to meet with general 
approval.” In this third edition the Terns seem to he accepted as laid down 
by Howard Saunders in the Cat. Birds Brit. Mus., Vol. XXV., 1896, but as 
that author did not recognise subspecies it seems probable that readjustment 
will later be made. That author was practically the only ornithologist to 
specialise in this group for over twenty-five years, and it would seem necessary 
to bring up-to-date the knowledge accumulated since the Cat. Birds Brit. Mus, 
was concluded. 
In the Proc. Zool. Soc. (Lond.), 1876, p. 638 et seq., Saunders first mono- 
graphed the SternincB, and noting the recent reviews, pointed out the difficulties 
attending the study of these birds owing to the shght differences present in 
their general coloration when adult, and the close resemblance of the immature 
of the species. This paper is most interesting, as Saunders there deals with 
the genera, and only admitting five — viz. Sterna, Hydrochelidon, Ncenia, Gygis, 
and Anous — commented upon the differences between the two Sooty Terns 
in the structure of their feet, and concluded: “It would strike anyone as 
absurd to separate these two Sooty Terns generically, seeing that their 
resemblance is so close that for some time even their specific characteristics 
were by no means well known ; yet, unless this is done, it is fully as inconsistent 
to separate them from true Sternce ... Of the discarded genera even the best 
seem to be based upon the size and shape of the bill — a very variable character 
in Terns, and one which, when taken alone, does not seem to be of so much 
value in this family as in many others.” When admitting Hydrochelidon he 
noted “ this very natural genus ” of which “ the most characteristic dis- 
tinctions are the short, rounded tail, and the long slender toes connected by 
deeply incised webs,” but regarding Gelochelidon, which he did not fidmit, 
he wrote : “In spite of its stout bill, the short and somewhat rounded lateral 
feathers of the tail, and the long hind toe, I do not think we can consistently 
allow a generic distinction without admitting a number of indifferent genera. 
. . . Although the shape of the tail is somewhat rounded as in Hydrochelidon, 
it must be remembered that 8 . caspia has a similar tail, and that both these 
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