284 APPENDIX. 



Hill, Esq., on the Shannon, in 1841, and is now in the 

 Museum of the Natural History Society of Dublin, but 

 had remained undistinguished specifically from a Black 

 Tern, Sterna nigra, shot at the same time, and sent along 

 with it. " Total length, to extremity of tail, about three 

 inches ; bill from base 10^ lines, from rictus one inch, five 

 lines ; greatest depths of both mandibles 2 J lines ; naked 

 portion of the tibia four lines." 



According to M. Temminck, it inhabits the bays and 

 gulfs of the Mediterranean, is very common about Gibraltar, 

 also visits the lakes, rivers, and marshes of the countries 

 beyond the Alps ; is very common on the Lakes of Lucarno, 

 Lugano, Como, Isco, and Guarda, and is seen on its pas- 

 sage on the Lake of Geneva. It is said to feed chiefly on 

 aquatic insects. 



Sterna leucoptera, Temm. Man. d'Ornith. ii. 747. 

 M'Coy, Ann. Nat. Hist. XV. 271. Yarr. Br. Birds, Sup. 60. 



FAMILY L. LARIN^E. 



GENUS CXLIV. GAVIA. MEW. 



340. GAVIA CAPISTRATA. MASKED MEW. 



Bill an inch and a twelfth in length ; tarsus an inch and 

 seven- twelfths ; wings two inches longer than the tail ; 

 bill and feet brownish-red ; primary quills white ; edged 

 and tipped with black. In winter, the back and wings 

 light bluish-grey ; the other parts white ; the head faintly 

 marked with grey. In summer, the colours similar, but 

 the fore-part of the head, cheeks, and throat, hair-brown, 

 bounded by blackish- brown. 



Adult, 15,. ., lift, l^, 1&, 1 



&, 



Two specimens, a male and a female, from Orkney, were 

 in Mr. Bullock's Collection. Another from Shetland was 

 presented, in 1831, by Mr. W. Lord, to the Zoological 

 . Society of London. In March 1833, one shot near Belfast 

 was exhibited by Mr. W. Thompson, and two others are 

 mentioned. This species, first distinguished by Mr. Tem- 

 minck, is smaller than Gavia ridibunda, with shorter and 

 more slender bill, and shorter tarsi. 



Brown-headed Gull. 



Larus capistratus, Temm. Man. d'Ornith. ii. 783. 

 Masked Gull. Yarrell, Brit. Birds, iii. 430. 



