TERTIALS— THICKHEAD 957 



the adults ill summer plumage wearing a lilack cap and having 

 the upper parts of the body and Avings of a more or less pale 

 gi-ey, while they are mostly lighter beneath. They generally breed 

 in association, often in the closest proximity — their nests, contain- 

 ing three eggs at most, being made on the shingle or among 

 herbage. The young are hatched clothed in variegated down, and 

 remain in the nest for some time. At this season the parents are 

 almost regardless of human presence and expose themselves freely. 



At least half-a-dozen other species have been recorded as occurring 

 in British waters, and among them the Caspian Tern, S. caspia, 

 which is one of the largest of the genus and of wide distribution, 

 though not breeding nearer to the shores of England than on Sylt 

 and its neighbouring islands, which still afibrd lodging for a few 

 pairs. Another, the Gull-billed Tern, ^S*. angllca, has also been not 

 iinfrequently shot in England. All these species are now acknow- 

 ledged, though the contrary was once maintained, to be inhabitants 

 of North America, and many go much further. 



Mr. Saunders {Cat. B. Br. Mus. xxv. pp. 4-152) recognizes 11 

 genera of the subfamily — Hydrochelidon with 4 species ; Phaethusa, 

 Gelochelidon, Hydroprocne and Seena with one each — these being 

 hitherto most generally placed in Sterna, to which last he allots 33 

 species, including among them 3 or 4 that are called in books 

 "Sooty Terns," but by sailors Egg-BIRD (p. 182), or, from their cry, 

 Wide-awakes, and seem as much entitled to generic separation as the 

 four above named ; Nsenia, a very aberrant form, consisting of but 

 one species, the Inca Tern, peculiar to the west coast of South 

 America ; Frocelsterna, Anoxic and Micranoiis containing the various 

 species of Noddy (p. 643), of which he now admits but 7 ; and 

 Gygis, composed of 2 species of purely white birds, almost restricted 

 to the southern hemisphere. 



TERTIALS, a name now almost wholly abandoned, but applied 

 by older writers to the innermost or proximal culiital remiges 

 (p. 780), especially when, as in many groups of Birds, they are 

 distinctly longer than the more distal or outer. 



TEUCHET and TEA\TITT, local names of the Lapwing (p. 504) 

 from its cry. 



THICKHEAD, Swainson's rendering in 1837 (Classif. B. ii. p. 

 249) of his own Pachy- 

 cephcda, a genus named 

 by him in 1824 [Trans. 

 Linn. Soc. xiv. p. 444, 

 note), to which about 

 50 species, all charac- Pachycephala. bopsaltria. 



teristic of and mostly (After Swainson.) 



peculiar to the Australian Region, have been referred, while some 



