I 



NATATORES. 383 



feet and legs slender ; webs of the toes deeply incised in front ; claws 

 rather strong. 



Dimensions. — Male. Total length (of skin), fifteen inches; wing, 

 eleven inches; tail, eight and a half inches. 



Colors. — Generally resembling those of Sterna panaya, Gm., but 

 much lighter. Front white, which color extends over the eyes; head 

 above, neck behind, and stripe before the eye, black. Entire upper 

 parts light cinereous ; darker on the coverts of the wings. Quills 

 cinereous, with a frosted or hoary aspect ; and on their inner webs, 

 with a wide longitudinal stripe of white. Outer web of first primary, 

 black. Tail light cinereous ; outer feathers white, tinged with cinere- 

 ous on their inner webs. Under wing-coverts, and entire other under 

 parts, white. Bill and feet, black. 



Hab. — Vincennes Island, Paumotu Group. Specimen in Nat. Mus. 

 Washington. 



We had hoped that the necessity of describing forms as new, though 

 intimately allied to long-known and well-established species, was at 

 an end, but in the case of the bird now before us, after careful compa- 

 rison, we give it the benefit of the doubt, and accordingly let it stand 

 as described. 



The only difference to be regarded as important, between the bird 

 now before us and Sterna panaya, is the lighter color of the former ; in 

 addition to which, the longitudinal band or stripe on the inner webs 

 of the quills is more distinctly defined, and there are some other minor 

 characters, which appear to be constant. It is, however, very similar 

 to the well-known species just mentioned. 



There are in the collection of the Expedition, two specimens of this 

 bird, both of which are from the Paumotu Islands, and are very simi- 

 lar in plumage. In the Museum of the Philadelphia Academj^, amongst 

 numerous specimens of Sterna panaya, from various localities, include 

 ing Mr. Gould's from Australia, we find one specimen only of this 

 species, which is labelled " des Mers de I'Oceanie," and was purchased 

 in Paris. Although at present disposed to regard it as a distinct spe- 

 cies, perhaps more local in its habitat than its near relative to which 

 we have alluded, we shall not be surprised, if the present bird is de- 



