Oedee IX.— LAEIFOEMES. 
This Order consists of sea-birds with webbed feet, which, resembling the 
medium-sized Petrels in general appearance, differ in the nature of their bills. 
This resemblance has been clearly shown to be due to homoplasy, and is not 
indicative of close relationship, as their general appearance would suggest. 
They have further been shown to be most nearly allied to the Charadriiformes 
although superficially very different-looking birds. 
Three families have been recently recognised, the Laridce^ Stercorariidce 
{—Catharactidce) and the Rhynchopidce, members of the last-named not entering 
into the Austrahan avifauna. 
The first-mentioned family has been divided into two subfamilies, Larince 
and SternincBf and these are certainly well-marked groups. The Sternince, or 
Terns, are well represented in Australia, and I propose here to sketch the 
attempts at classification, and the present state of our knowledge, to enable 
Australian ornithologists to follow my treatment. 
Terns vary in size but not much in coloration, the majority being pale- 
grey above and white below with more or less black caps, the remainder being 
brownish or black above and in some cases also below. The chief differences 
lie in size, length and strength of biU, size of legs and feet, and more or less 
webbing of the latter. They all agree in having forked tails, varying in the 
depth of the fork in relation to the outer lateral feathers, which are very 
often so long that they have been given a name to distinguish them, 
viz. streamers. 
On account of their similarity of coloration, systematists have been long 
troubled as to the value of the differences observed. Until 1822 they were aU 
classed in the Linnean genus Sterna ; Boie, in that year, working upon 
European forms, indicated several genera ; in 1826, Stephens, probably 
ignorant of Boie’s work, proposed a couple of others, while the same year Boie 
added one more ; in 1829 Kaup again divided Sterna, introducing new names 
for similar divisions to those of Boie ; two years later Brehm again renamed 
Boie’s and Kaup’s genera, while the succeeding year Wagler, as well as 
again renaming the previously-named genera, indicated others among the 
extra-European Terns. This left very little for anyone else, and I can only 
note one generic name introduced in this group since 1846. In 1862 Cones 
{Proc. Acad. Nat. Sci. Philad., pp. 535-559) reviewed the Terns of North 
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