222 AVES: TUBINARES. — XXXII. 
664. S. paradisza Briinnich. Arctic Tern. Bill carmine 
throughout; plumage as in hirundo, but darker below. L. 14 to 
17. W.10to11. T.7to 8. B.14. Smaller than hirundo, but 
tail proportionally much longer. Arctic, S.to N.Y. (£u.) 
ece. Outer tail-feather with both webs white. 
665. S. dougalli Montagu. RosEate Tern. Bill black, usu- 
ally orange at base below; mantle very pale; rosy-tinted below in 
breeding season, L.14to17. W.9}. T.5to8. B.14. Atlan- 
tic coast. (Eu.) (To Dr. McDougall, of Scotland.) 
aa. Wing less than 7; tail deeply forked, about half wing. (Sternula Boie.) 
666. S. antillarum Lesson. Least TERN. Bill yellow, usually 
tipped with black; a white frontal crescent between cap and bill; 
shafts of two or more outer primaries black above; mantle pale 
gray; very small. L.8or9. W. 6}. T. 3}. B.14. E. U.S, 
chiefly abundant coastwise. 
336. HYDROCHELIDON Boie. (vdap, water; yeArdav, swallow.) 
667. H. nigra (L.). Brack Tern. Head, neck and under parts 
black (in full plumage) ; wings and tail above dark like the back ; 
crissum white. L. 10. W.8. T. 3}. B. 1,;. N.Am., chiefly 
inland. (Eu.) The American var. surinamensis (Gmelin) is 
darker than the European form. 
Famity CXXIX. RHYNCHOPIDA. (Tue Skimmers.) 
Gulls with the lower mandible much longer than the upper, com- 
pressed like a knife-blade; its two sides completely soldered to- 
gether; the upper edge as sharp as the lower, and fitting in a 
groove in upper mandible; tip of bill obtuse; upper jaw com- 
pressed, movable at base; tongue very short, stumpy. Wings very 
long. Otherwise similar to the terns. One genus, with 3 species. 
337. RHYNCHOPS Linneus. (fvyxos, beak; ay, face.) 
668. R. nigra L. Biack Swimmer. CutTwater. Glossy 
black; white below; lower mandible about an inch longer than 
upper. L. 17 to 20. W. 15. T. 5, sharply forked. B. 24. 
Tropical Amer., N. to N. J., abundant southward. 
Ornper XXXII. TUBINARES. (THE TvuBE-NosED 
SwIMMEBS. ) 
Nostrils tubular; bill with the upper mandible hooked, its cover- 
ing composed of several pieces separated by deep grooves. Other- 
wise essentially like the Longipennes so far as external characters 
are concerned. 
a. Nostrils united in a double tube, placed horizontally on the culmen. 
PROCELLARIID#, 180. 
