654 



MR. H. SAUNDERS ON THE STERNIN.E. [June 20, 



Thalasseus elegans, Gamb. Journ. Phil. Acad. ser. 2, vol. i. p. 228 

 (1849) ; Coues, Pr. Phil. Acad. 1862, p. 540; Ibis, 1864, p. 389 

 (San Salvador); Salvin, Ibis, 1866, p. 198 (Fonseca Bay). 



Sterna comata, Phil. & Landb. Wieg. Arch. 1863, pt. 1, p. 126. 



Sterna, galericulata (part.), Scl. & Salv. P. Z. S. 18/1, p. 569; 

 Coues, Key, p. 319 (1872), B. N.W. Am. p. 671 (1874). 



A recent examination of Lichtenstein's type of S. galericulata has 

 shown it to be identical with the Cayenne Tern, S. maxima, Bodd. ; 

 so that Gambel's name must be restored. It occurs on the Pacific 

 side of America, from the Gulf of California to the coasts of Peru 

 and Chili; but I consider that the bird found on the Atlantic coast 

 is distinct, although closely allied. Three specimens which I have 

 examined in Mr. Salvin's collection, from the Pacific side, and two 

 others in the British Museum, from Chili or Bolivia, all agree in 

 having a longer foot and tarsus^-2 inch) than the Atlantic bird ; 

 but the principal^ distinction is in the bill ; the angle of the lower 

 mandible being well in advance of the front portion of the nostril 

 (•5 inch diagonally) in the Pacific birds,' whereas the angle is 

 almost directly under the nostril in the Atlantic form ; the colour 

 of the bill also is red or orange in the former and y ellow in the 

 latter, even in tolerably fresh specimens, which still preserve the 

 beautiful roseate tint of the underparts. It is perhaps as well to 

 mention that these remarks are founded upon perfectly well-made 

 skins, the tips of the mandibles being in their proper relative posi- 

 tions ; otherwise it might be supposed that the under mandible had 

 been unduly drawn back ; the difference, however, on comparison, is 

 very striking, as will be seen by the annexed woodcut. 



Fis. 1. 



Head of Sterna eurygnatha. 



As the Atlantic bird has not hitherto been distinguished, I pro- 

 pose to call it 



Sterna eurygnatha, sp. nov. 



S. similis Sternse eleganti, sed rostro flavo et mandibidee angulo 

 sub narium apertura antica posito distinquendu. 



[18] 



