222 AVES: TUBINARES. — XXXIII. 
664. &S. paradisezea Briinnich. Arctic Tern. Bill carmine 
throughout; plumage as in hirundo, but darker below. L. 14 to 
17. W.10to11l. T.7to 8. B.14. Smaller than hirwndo, but 
tail proportionally much longer. Arctic, S.to N.Y. (£w.) 
eee. 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.93. T.5to8. B.1}4. Atlan- 
tic coast. (Hu.) (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.64. T. 3f. B.14. E. U.S, 
chiefly abundant coastwise. 
336. HYDROCHELIDON Boie. (vdwp, water; yedAdav, swallow.) 
667. H. nigra (L.). Buacx 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. (Hu.) The American var. surinamensis (Gmelin) is 
darker than the European form. 
Famity CXXIX. RHYNCHOPIDA. (THE SKI_MERs.) 
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; dy, face.) 
668. R. nigra L. Buiack Swimmer. CuTwaTerR. Glossy 
black ; white below; lower mandible about an inch longer than 
upper. L. 17 to 20. W. 15. TI: 5, ‘sharply forked. Bo 25. 
Tropical Amer., N. to N. J., abundant southward. 
OrpER XXXII. TUBINARES. (Tue TusBeE-NosED 
SWIMMERS. ). 
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#, 1380. 
