Tribe BEACH YPTERX. 
Family C 0 L Y M .1) I D A E - l 
Ch. _Bill more or less long and compressed ; the nostrils are linear or rounded, and situated in a lateral groove ; tail rudimen¬ 
tary or short; tarsi much compressed ; anterior toes long, with the interdigital membrane more or less full, the outer longest.; 
hind toe short, free, with a hanging lobe ; claws broad, depressed, buried in the body. 
The species are remarkable for their powers of swimming and diving; their ease and grace¬ 
fulness on the water is in strong contrast with their awkwardness on land. 
The following are the characters of the two sub-families, Colymbinae and Podicipinae: 
Colymbinae. —Bill long, rather strong, much compressed, with the point acute ; nostrils basal, 
linear ; tarsi much compressed ; toes long and webs full; tail short; lores feathered. 
Podicipinae. —Bill generally long and rather slender, compressed and pointed ; nostrils 
situated in a groove, oblong and narrow ; tarsi compressed; toes long and broadly lobed ; tail 
wanting, or very rudimentary ; lores naked. 
Sub-Family COLYMBINAE.—The Divers proper. 
Ch.—B ill about the length of the head, rather stout, much compressed, and acute ; nostrils basal, linear and pervious ; wings 
of medium size, narrow and pointed, first quill the longest, reaching far beyond the scapulars ; tail short and rounded ; tarsi 
very much compressed ; entire tarsi and base of toes reticulated ; toes long, the anterior ones united by regular webs, the claw 
of the middle twice as long as broad ; hind toe short, edged with a narrow membrane. 
These birds excel all others in their rapidity of diving, and the great progress they are able 
to make under water. Only one genus in this sub-family is recognised by authors. 
COLYMBUS, Linnaeus. 
Colymbus, Linn. Syst. Nat. 1735. Type C. arcticus. 
As the character of the sub-family include those of the single genus Colymbus , it is not neces¬ 
sary to repeat them. 
They are abundant during summer in the high northern latitudes, both on the seacoast and 
on inland lakes; in winter they migrate to the south. They are solitary in their habits, keen 
sighted, and very difficult of approach; their flight is strong, rapid, and direct. 
The species of this genus have the following characters : 
Bill strong, compressed, nearly straight, a groove on the under mandible, continued from 
the junction of the crura to near the point; head and neck dark bluish green, a small 
patch of white feathers on the throat in front, also a larger one on each side of the 
neck.... C. glacialis . 
Bill rather strong, much like that of the above species, but smaller and without the 
groove underneath ; head and neck bluish grey, a large space of purplish black on the 
front part of the neck... C. arcticus. 
Bill not so strong as in either of the above named species. Adult plumage not 
known ......— C. pacificus. 
Bill straight and slender; head and neck clear light bluish grey, hind neck marked with 
white and greenish black, on the fore part of the neck is a large patch of dark reddish 
brown. C. septentrionalis. 
1 Prepared by Mr. George N. Lawrence, of New York. 
