222 AVES: TUBINARES. XXXIII. 



664. 5. paradisaea Briinnich. ARCTIC TERN. Bill carmine 

 throughout; plumage as in hirundo, but darker below. L. 14 to 

 17. W. 10 to 11. T. 7 to 8. B. ij. Smaller than hirundo, but 

 tail proportionally much longer. Arctic, S. to N. Y. (Eu.) 



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. 14 to 1 7. W. 9. T. 5 to 8. B. l. 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. 8 or 9. W. 6J. T. 3. B. l. E. U. S., 

 chiefly abundant coastwise. 



336. HYDROCHELIDON Boie. ({J&op, water ; ^eXtSwi/, swallow.) 



667. H. nigra (L.). BLACK 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. SJ. B. 1^. N. Am., chiefly 

 inland. (Eu.} The American var. surinamensis (Gmelin) is 

 darker than the European form. 



FAMILY CXXIX. RHYNCHOPID^l. (THE 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. RHYNCHOFS Linnaeus. (puyxos, beak ; oty, face.) 



668. R. nigra L. BLACK SWIMMER. CUTWATER. 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. 



ORDER XXXIII. TUBINARES. (THE TUBE-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. 



o. Nostrils united in a double tube, placed horizontally on the culmen. 



PKOCELLARIID^E, 130. 



