1016 STERNA FLUVIATILIS. 



legs and feet are orange, and in all the webs are lighter than the tarsus. Two examples shot in June : bill blacker 

 than in April, with little orange at the gape; tarsus dusky brownish, mingled with yellow. 



Length 12-5 to 13-6 inches; wings (all abraded) 9-5 to 10-2; tail 4-6 to 5-2, depth of fork 2-0 to 2-2, outer feathers 

 1-0 longer than the penultimate; tarsus 0-7 to 0-8 ; middle toe 07, its claw (straight) 0-3 ; bill at front 1-2 to 

 1-30, to gape 1-7 to 1-85. 



In all these specimens (seven) the forehead and lores are pure white, becoming gradually mixed with blackish on the 

 crown ; the occiput, nape, and sides of the head behind the eye brown-black, with also a black edging in front of 

 the eye : a dark-brown band along the ulna ; back blue-grey in some, mixed with brownish-tipped feathers, the 

 remains of the last season's plumage ; the tails which are in new feathers in the April specimens, have the outer 

 webs dark grey, paling successively towards the centre, the tips white ; the central tail-feathers, the coverts, and 

 rump are blue-grey, paler than the bach ; under surface and hind neck pure white. 



Obs. An example from Cayenne measures as follows — wing 10-6 inches, tail 5-5, tarsus 0*73, middle toe 07, bill 

 to gape 1"9 ; one from the Cape — wing 10'7, tail 5 - 7, bill to gape 1-9. I have given Dr. Scully's measurements 

 of Tarkaud examples above. An example among the immature birds here described was identified by Mr. Howard 

 Saunders as the Common Tern ; and since my return to England this gentleman has not altered his opinion. I 

 have compared my series with examples of the Common Tern from various collections, and they appear to assimi- 

 late better with that species than with any other ; but there remains the curious fact of the bills becoming blacker 

 towards the summer instead of redder ; the June examples, which had blacker bills and darker legs than the April, 

 had, however, not begun to acquire the black cap, though the tail-feathers and primaries, except the first two 

 (which in all Terns are the last to be shed ), had been newly acquired. The assumption of the black bill in the 

 summer points to a connection with/S'. longipennis, Nordmann, a North-east Asian species, which Mr. Hume says 

 is found on the coasts of India. It is to be hoped that mature examples will be procured in Ceylon at a future 

 period, and more light thrown upon the identity of the species. In none of my specimens is the gonys as long 

 as in the above examples from America. Two examples of >S'. longipennis from Kamtschatka, in Mr. Saunders's 

 collection, measure as follows: — wing 11-0 to ll - 2; tail 6 - 5 to 6-8; tarsus 08 ; bill to gape 1-9. The bills 

 are black, palish at the base beneath, and the forehead, head, and nape^ire black. It is a slenderer bird than the 

 Common Tern. 



Mr. Saunders has lately (I\ Z. S. 187G, p. 649) described an allied species to the Common Tern from Thibet and Lake 

 Baikal, under the name of Stcma tibetana. It resembles the former to a great extent, differing "in having the 

 sides of the neck, shoulders, and flanks clear grey, which assumes a darker and more vinous tint on the breast and 

 abdomen ; the mantle and wings are also much darker ;" bill and feet as in the Common Tern. 



The Arctic Tern (S. macrura, Naum.), which has often been confounded with the present species, has the bill entirely 

 red in the summer, the tarsus much shorter, not exceeding 0-55 inch, and the tail reaches beyond the closed wings. 



Distribution. — A specimen of the Common Tern was sent to the Calcutta Museum by R. Templeton, Esq., 

 in 1846, and since that time until 1875 no record of its occurrence in the island was published, both Layard 

 and Iloldsworth omitting to notice it in their lists. In October 1874 I met with a number in Kottiar Bay, 

 near Trincomalie, and secured specimens. I did not notice it then until the height of the netting-season, 

 when great numbers, mixed with the Gull-billed and some Crested Terns, used to frequent the bays on each 

 side of the Fort, and live on the sardines which swarmed in shallow water near the beach. They disappeared 

 in June, about the time that large flocks of the Roseate Tern passed over that part of the coast; but the 

 following season they were again about the port ; but I never saw them inside the harbour. In March 1876 I 

 think 1 identified it on the wing in Jaffna Lake, but procured no specimens. From all accounts it seems to 

 be rare in India ; for though Dr. Adams informed Jcrdon that it was common on the Indus, rivers of the 

 Punjab, and lakes of Cashmere, Mr. Hume never once saw it in his tour through Sindh and exploration of 

 the Indus. Jcrdon states that it is rare in South and Central India, having only been seen by him from the 

 lake at Ootacamund ; but no one else has met with it since. In Kashgharia Dr. Scully found it abundant, 

 arriving there in April, breeding in April, and leaving again in September. It occurs to the eastward in 

 China, on. the rivers of the interior, according to Pere David ; and Swinhoe met with it at Hankow on the 

 Yang-tsc-kiang. It does not appear to range northward into Siberia, being there replaced by <S. tibetana. From 

 Turkestan, in the eastern portion of which it breeds, according to Severtzoff, it ranges into Asia Minor, through 

 Persia, and is found on the Caspian Sea and on the Black Sea, Sea of Marmora, and Bosphorus, arriving in 

 these waters in April, and probably breeding there. It likewise occurs in the Mediterranean islands, and on 



