242 BACKBONED ANIMALS. 
the single egg is placed. The nest is often occupied by a 
family of rabbits. 
VaLuE.—Auk and puffin leather, oil, and fur. 
Loons (Colymbide).—The great northern diver or loon 
(C. torquatus) is a familiar example, ranging throughout 
the whole of North America. They dive with great skill, 
and swim under water a quarter of a mile, faster than a 
man can row; are good ‘fliers, but move slowly on land. 
The Grebes (Podicipitide) are abundant in northern 
America, and common in many countries ; they are dis- 
tinguished by the structure of their feet; the membrane, 
instead of uniting the toes, being 
cleft nearly to the base of the lat- 
ter, forming membranous margins 
(Fig. 281). The bill is long and 
slender. The crested grebe (P. 
cristatus) attains the length of about 
twenty-four inches, and extent of 
wings thirty-four. The head is or- 
namented with a large double crest 
of brown feathers. They frequent 
the fresh-water lakes and streams, 
Fic, 281.—Foot of grebe and are powerful swimmers, often 
(Podiceps), showing remaining under water with the tip 
swimming membrane : ‘ 
Ga each:tae. of the bill exposed when pursued. 
The nest is formed of rushes in the 
water, and often floats about. The eggs number from 
two to seven, and the young follow the mother as soon as 
hatched, often taking refuge upon her back. 
Notr.—The nest of the Castanean grebe (P. cormutus), according 
to Fouray, is a perfect raft, and is paddled about by the mother. 
The eared, horned, Western, and red-necked grebes are 
American species. 
VALUE.—Skin as fur, muffs, etc. 
