212 
ZOOLOGY, 
on shore they have an awkward gait. Tliey lay but a sin- 
gle egg, and some species do not lay their egg on the rocks, 
but bear it about in a pouch-like abdominal fold. The 
penguins, however, differ so much from the other divers 
that they are now often ranked as a separate group called 
Fig. 250.— The Great Auk. 
Sphenisci. There are twelve species of penguins, divided 
among three or four genera. 
The guillemots (Fig. 248, Uria grylle), auks, and puffins 
(Fig. 249, Fratercula arctica) are characteristic arctic birds, 
ranging from Labrador northward, and have great powers 
of flight. The gare fowl^ or great auk {AUa i77i])e7inis, 
