OiiDER PYGOPODES. 



THE DIVING BIRDS. 



TiiF, PyfTopodos incliido tliroi! very distinct families of birds, nil of which are 

 well reitrosontcd in North Aini'rica. Some authors include in this Order the Pen- 

 guins (Sp/irimridd); hut they lutssess so many ix'culiar features as unquestionably 

 to entitle them to the rank oi a distinct Order {Sjilicnisci). 



Tlie faniilios of Tyj^opodes which come within the scope of the present work may 

 be defined as follows : — 



A« llnlhix priKint. 



1. Podicipidas. Tnos Inlu'd, the nulls lliit, broad, anil rnundi'd nt lips ; tail iiidinientavy ; a 



Ijarc loral stripe extending,' from tlie bill to \.\w eye ; bill variable in I'orni, but always 

 more or less elon},'afed. 



2. Urinatoridae. Toes fully webbed, I lie nails curved, aciUe, claw-like ; tail normal ; lores 



comjiletely and compactly .'eatliercd ; bill elongated, acute, compressed. 

 B< JIkUhx iihunnt. 



3. Alcidae. Toes fully webbed, the cla\v .rvetl and acute ; tail normal ; lores feathered ; 



bill excessively variable in form. 



FAMILY I'OmCTPID/E. — The (Jkhrks. 



CllAH. Swimmers resemblinj,' the Loons in the posterior insertion of the legs, 

 Init the toes lobate and semipalmate, instead of com]»letely webbed, the claws 

 broad. Hat, and nail-like, instead of normally narrow and curved. P>ill varial)li! 

 in shape ; nostrils variable, but without an overhanging lobe ; wings very short 

 and concave, the prinicaries covered by the .secondaries in the closed wing; tiiil 

 rudimentary, consisting of a mere tuft of downy, loose-webbed feathers, withniit 

 perfectly formed rectrices ; plumage of the lower surface remarkably silky ami 

 lustrous, usually white. 



The Grebes have by many authors been included in a single genus — rndicrps 

 (= Coli/mfms) — while a majority of writers admit but two — Podiceps and I'mH- 

 hjinhus. The former, however, in this comprehensive sense, contains many extremely 

 dissimilar forms, and should, it appears to us, be sididivided, as has been done by 

 Dr. Cones in his monograph of the family ("Pr. Philad. Acad." 1802, p. 230), Tlic 

 following North American genera appear to lie rather well characterized. CoJymhvs, 

 it may be remarked, a))])roaclies JErlivinphonis through the South American C. mnjor. 

 BonD., a species havii.g the bill of jEchmopliorus, but the coloration and shorter 

 neck of a true Colymhis. 



