LAEID^E. LXTTT. 153 



10. HYDROCHELIDON, Boie. BLACK TERNS. 



1. H. I ar if or mis, (L.) Coues. BLACK TERN. Head, 



neck and under parts black (in full plumage); wings 

 and tail above plumbeous like the back; crissum white; 

 small; L. 10; W. 8 to 9; T. 3. N. Am., chiefly inland. 

 [H. fissipes, (L.) Gray.] 



2. H. nigra, (L.) Gray. WHITE -WINGED BLACK TERN. 

 Wings whitening along border of fore -arm; tail and 

 upper tail coverts white. Straggler from Europe, a 

 single specimen lately taken on Lake Koshkonong. 

 (Ludomc JTunllien.) \H. leucoptera, (Meisn.) Boie.] 



//. RHYNCHOPS, Linnaeus. SKIMMERS. 

 1. fi. nigra, L. BLACK SWIMMER. CUTWATER. Glossy 

 black; white below; lower mandible about an inch 

 longest, compressed like a knife - blade, obtuse at end; 

 L. 16 to 20; W. 15; T. 5, sharply forked. Coast, 

 abundant southward. 



' 



ORDER S.-PYGOPODHSTJV/v,., . 



(The Diving Birds.) ' '" >S| I T y 



Feet palmate or lobate; tibiae feathered, buried 44 ft^f /,\ 

 skin nearly to the heel joint, hence the legs are set very 1 1 ^S 



far back, and the birds are scarcely able to walk at all 

 on land; hind toe small, elevated, often wanting. Nos- 

 trils developed; bill of various forms, horny, not lamellate 

 nor serrate ; no gular pouch. Wings very short, scarcely 

 reaching the base of the very small or rudimentary tail. 

 Swimmers, many of them noted for their powers of div- 

 ing. We here omit the three - toed family of ALCID^E, 

 the Auks, they being strictly maritime and mostly 

 northern. The twenty -one known species all occur in 

 America. 



