no Af.i.F.N's NATURALIST'S LIBRARY. 



are often pursued under the water with as much dexterity as 

 the Swallow chases an insect in the air. The Razor-bill flies 

 under the water aided by its webbed feet; it is capable of 

 remaining under the surface for a long time, and when sub- 

 merged not only catches fish, but searches for crustaceans, 

 molluscs, &c. The note of this bird, which is rarely heard, 

 may be described as a low croaking sound." 



Nest. None. The Razor-bill places its eggs on the rocks, 

 but always, if possible, in some niche or crevice, sometimes 

 far out of reach, and seldom in the open, though Saunders 

 once saw an old Cormorant's nest appropriated by a Razor-bill. 

 Both male and female incubate. 



Egg. One only, differing in shape from that of the Guille- 

 mot, and the extraordinary variation in colour is not so marked 

 as in the eggs of the latter bird. A reliable test for their identifi- 

 cation consists in the fact that, when the egg of the Razor-bill 

 is held up against the light, and looked at through the blowing- 

 hole, the inside always appears green, whereas the inside of a 

 Guillemot's egg generally appears to be yellowish-green, though 

 greenish eggs of the latter bird have often a pervading tint of 

 green reflected through by the external colour of the egg. Mr. 

 Robert Read writes : " The Razor-bill lays its eggs on the bare 

 rock, without any sign of a nest, like the Guillemot. The eggs 

 are, however, usually placed in more sheltered positions than 

 those of the latter bird, such as in a corner or hollow among the 

 rocks, or under a projecting boulder. Some of the eggs with 

 the red ground-colour are very handsome, but I have found 

 them mingled with those with white and every intermediate 

 shade of ground-colour on the same rocks. Some varieties of 

 the Razor-bill's eggs are not easy to distinguish from those of 

 the Osprey." 



THE GREAT AUKS. GENUS PLAUTUS. 

 PlautuS) Briinn. Zool. Fund., p. 78 (1872). 



Type P. impennis (Linn.). 



Only a single species of the genus Plautus is known. Once 

 plentiful within a limited latitude, it has become extinct within 

 the present century, and, in spite of hopes that some indi- 



