216 THE ZOOLOGIST. 
confusing subdivisions. First, Wagler took the MS. description, 
or perhaps even the type specimen, of J. R. Forster's Sterna 
serrata, which he identified, and correctly, with S. fuliginosa, but 
as that individual specimen had a claw somewhat notched and 
jagged from contact with rocks, he formed for its reception the 
genus Onychoprion (Isis, 1832, p. 277), from ow, nail, xpiav, a saw. 
He then took another of Forster’s types, named in his MS. Slerna 
guttata, which this time happened to be an example of S. /uli- 
ginosa, in which the accidental serration above referred to was 
not observable: here it seemed to him was another structural (!) 
difference, on which he accordingly based the genus Planetis 
(Isis, 1832, p. 1222), from aamros, wandering. Not yet satisfied, 
he took a third specimen of S. fuliginosa, and, almost on the 
same page, gave it generic distinction under the name of Hali- 
plana (Isis, 1832, p. 1224), from aasgaavos, sea-wandering. That 
was pretty well for one systematist’s work with a single species: 
others have placed the same bird in two other genera besides 
Sterna, but let that pass. 
With regard to the propriety of separating the Sooty Terns 
generically from the other Sea Terns, I would remark that I can 
find no structurab difference in the former, their only peculiarity 
consisting in their coloration,—a distinction insufficient in my 
opinion for the formation of a genus,—and even in that respect 
there is a species found at Alaska, Sterna aleutica, which, with 
head markings and mantle similar to those of JS. fuliginosa, 
has a white rump and tail, thus forming a connecting link. But 
although there is no well-defined structural difference between 
S. fuliginosa and the typical Sea Terns, there actually exists 
a real noticeable structural variation in the formation of the 
feet of such closely allied-species as S. fuliginosa and S. anes- 
iheta—forms which the most persistent genus-maker would 
hardly venture to place in different genera— yet it is clearly 
shown that they differ more markedly ¢nfer se than they do from 
typical Sterna. 
Under these circumstances, I would submit it to the judgment 
of ornithologists whether it is not advisable to disregard Wagler’s 
genera, and to retain the Sooty Terns in the genus Sterna. 
