SENEGAL TERN. 
251 
fore consider them as distinct, at least until further 
information proves the contrary. In reference to 
Mr. Selby’s account of the S. I \irundo , we shall 
merely point out in what respects our present bird 
differs. The bill measures only of an inch from 
the forehead to the tip, instead of one inch and a 
half : there are no “ long occipital feathers,” those 
of our bird being in no respect lengthened. The 
under plumage, instead of being pure white, with a 
tinge of grey only on the breast, is only pure white 
on the chin, sides of the head, and beginning of the 
throat ; from thence a very slight shade of pearl- 
grey commences, which gradually increases over 
the breast, body, and belly, where it is darkest, and 
where it terminates : the under tail- covers are like 
the upper, pure white : the wings are slightly longer 
than the tail, and the colouring of both agrees with 
Mr. Selby’s description ; but the same may be said 
of two other species now before us, one from the 
arctic regions, and the other, as supposed, from 
India. All these have a marked difference in their 
size, and, with other peculiarities, create a belief 
that they are specifically distinct. The bill of this is 
very slender, and more curved than in the others. 
Total length, 12 inches ; bill, front, 1 ^ ; gape, 
2 ; wings, 10, being about f longer than the tail ; 
tarsus hardly T 7 5 ; middle toe and claw, 1 ; hind 
ditto, j’j, ; tail, base, 6 ; depth of the fork, 2 T \ ; 
outer feather 1 longer than the others. 
