131 
their breeding-place the inland waters of some marsh or swampy 
island in the interior of the country. Their interest is also much 
added to by the circumstance of their being subject to seasonal 
changes in the colouring of their plumage. 
382. CHROICOCEPHALUS RIDIBUNDUS . . . . Vol. VY. Pl. LXIV. 
Buack-HEADED GULL. 
A common and resident species. 
383. CHROICOCEPHALUS PHILADELPHIA. . . . Vol. V. Pl. LXV 
BonaPARte’s GULL. 
An ozcasional yisitant from its native country, North America. 
Genus HyprocoLevs. 
Instituted for our well-known Little Gull. 
So4. HyDROCGL&US MENUTUS. . . . . «.« Vol. V. Pl. LXVI. 
Litrte Guu: 
_A tolerably regular winter visitant, never breeding in Britain. 
Genus XEMA. 
The beautiful arctic Gull named after the late Mr. Sabine is the 
type of this genus. 
SOMMGEMA SARIN c) 6 eo.3 ek. * es et OL VP Lee 
SABINE’s GULL. 
An occasional visitor to our islands. 
Subfamily STERNIN A. 
In this subfamily are contained the various forms of Terns or Sea- 
Swallows as they are popularly termed. Ten species are figured 
under six genera:—AHydroprogne, Actochelidon, Sterna, Sternula, 
Gelochelidon, and Hydrochelidon. 
Genus HypRoproGne. 
886. HyproprocnE caAsprIA . . . . .- . Vol. V. Pl. LXVIUII. 
Caspian TERN. 
An accidental visitor. 
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