Genus—G ELOCHELIDON. 
Gelochelidon Brehm, Vogel Deutschl., p. 771, 1831 . . Type G. nilotica. 
(Also spelt Chelochelidon Brehm, and Gelichelidon Gray, 
List Spec. Birds Brit. Mus., pt. ni., p. 176, 1844.) 
Laropis Wagler, Isis 1832, p. 1225 . . . . . . . . Type G. nilotica. 
Larger Terns, with short stout bill, long wings, short tail, and long legs. The 
diagnostic features of this genus are the short stout bill and short tail with 
feet fully webbed. The metatarsus is longer than the middle toe and claw, 
but shorter than the culmen, which is also shorter than the head. The tail is 
deeply forked, but still less than half the length of the wing. 
Regarding the nomenclature to be used for these large short-tailed Terns, 
I have written in the Nov, Zool. (Vol. XVII., p. 497, 1910) advocating the 
claim of Hydroprogne for the Sterna tscliegrava Lepechin. To again review the 
subject I would note Thalasseus was proposed for three species caspia, cantiaca, 
and anglica ; no type was designated. Brehm, nine years afterwards, 
separated these three species, allotting a generic name to caspia, another to 
anglica, and retained Thalasseus for cantiaca. According to the laws now in 
force this action must be endorsed, and it is worthy of note that Gray designated 
as type of Thalasseus, S. cantiaca {List Gen. Birds, p. 79, 1840), and in the 
Isis, 1844, p. 181, Boie, the author of the name Thalasseus, himself endorsed 
Brehm’s and Gray’s action. I can see no reason whatever against Brehm’s 
restriction, and would accept S. cantiaca as type of Thalasseus. In the Skizz 
Entwick-Gesch. Nat. Syst., 1829, Kaup had proposed new generic names for 
Terns without recognition of Boie’s prior work : thus Actochelidon was intro- 
duced for S. cantiaca, Thalasscea for S. dougalli, and Hydroprogne for S. caspia 
and aranea. The last named was diagnosed from S. caspia, and S. aranea was 
added from literature only. The description of the generic charact)6rs of 
Hydroprogne refer only to S. caspia; and Gray, in the Gen. Birds, Vol. III., 
p. 658, January, 1846, noted that S. caspia Pall, was the type of Hydroprogne, 
at the same place writing that S. cantiaca was the type of Thalasseus Boie. 
When Brehm {Vogel Deutschl., pp. 767 et seq., 1831) divided Boie’s genus 
Thalasseus, he proposed Syhchelidon for 8 . caspia, and introduced Gelochelidon 
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