284 VERTEBRATES : BIRDS. 



Fi *- I5 - The Genus Mormon Puf- 



fins has the bill short, com- 

 pressed, very high, and the sides 

 obliquely grooved. Four spe- 

 cies or more belong to the north- 

 ern portions of America. 



The Arctic Puffin, M. arctica, 

 Illig., is eleven and a half inches 

 long, and the wing six and a 

 half inches. Puffins make their 



Puffin, M. arcttca, Illig. 



nests in burrows, which they dig 



to the depth of four to five feet in some cases. Each 

 lays but a single egg in a season. 



The Genus Uria Guillemots has the bill rather 

 long, straight and pointed, wings short, and claws curved. 

 Six species belong to North America. 



The Black Guillemot, U. grylle, Lath., of the North 

 Atlantic, is thirteen inches long, and the wing six and a 

 half inches ; color black ; a white patch on the wing. 



The Genus Brachyrkamphus comprises the Short-billed 

 Guillemots. Six species inhabit the North Pacific. 



The Genus Mergullus has the bill short, thick, and 

 slightly lobed on its edges. It contains the Little Auk, 

 Sea-Dove, or Dovekie, M. alle, VieilL, of the North At- 

 lantic, which is seven and a half inches long, and the 

 wing four and a half inches ; breast and upper parts 

 brownish black ; under parts white. 



Evidences of extinct species of birds exist in the rocks 

 of both this and other countries, and some species have 

 become extinct in comparatively recent times.* Tracks 

 of birds which lived in the Triassic Period are common 

 in the Sandstone of the Connecticut valley. 



* The Dodo was a large bird, weighing about fifty pounds, and with rudi- 

 mentary wings, which in the seventeenth century inhabited Mauritius and 

 adjacent islands ; but of which there is now not even one perfect specimen 



