308 CHARLES DARWIN 



water the surface was blackened, and a noise proceeded from 

 them as of human beings talking in the distance. 



There are several other species of petrels, but I will only 

 mention one other kind, the Pelacanoides Berardi, which 

 offers an example of those extraordinary cases, of a bird 

 evidently belonging to one well-marked family, yet both in 

 its habits and structure allied to a very distinct tribe. This 

 bird never leaves the quiet inland sounds. When disturbed 

 it dives to a distance, and on coming to the surface, with the 

 same movement takes flight. After flying by a rapid move- 

 ment of its short wings for a space in a straight line, it drops, 

 as if struck dead, and dives again. The form of its beak and 

 nostrils, length of foot, and even the colouring of its plum- 

 age, show that this bird is a petrel: on the other hand, its 

 short wings and consequent little power of flight, its form 

 of body and shape of tail, the absence of a hind toe to its 

 foot, its habit of diving, and its choice of situation, make it 

 at first doubtful whether its relationship is not equally close 

 with the auks. It would undoubtedly be mistaken for an auk, 

 when seen from a distance, either on the wing, or when div- 

 ing and quietly swimming about the retired channels of 

 Tierra del Fuego. 



