212 



ZOOLOGY. 



on shore they have an awkward gait. They lay but a sin- 

 gle egg, and some siiecies 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 

 tliat they are now often ranked as a separate group called 



Fig. 550.— The Great Auk. 



Sphenisci. There are twelve species of penguins, divided 

 among three or four genera. 



Tlie guillemots (h'ig. 248, Uria grijlle), auks, and puffins 

 (Fig. 249, Fratercula arc/ica) ai'e characteristic arctic birds, 

 ranging from Labi-athir northward, and have great powers 

 of flight. The gare fowl, or great auk [Alca impeimis, 



