242 CINCLIDJE. 



perceivable muscular effort, but also, as has been asserted, 

 of walking at the bottom when under water with the same 

 ease that other birds walk on dry land. 



The Dipper frequents clear, rocky mountain-streams, 

 diving with great facility, and feeding principally, if not 

 entirely, upon the various aquatic insects and small fresh- 

 water-mollusks with which they abound. 



The muscles and other parts of the vocal organs, as shewn 

 by a specimen sent for dissection from Wales by Mr. John 

 Morgan, are similar to those of a Thrush ; and there is 

 nothing in its internal structure that could induce the belief 

 that it possessed the powers which, as mentioned above, 

 have been so frequently attributed to it. Its short wings are 

 well adapted for progress under water ; but, clothed with its 

 feathers, the specific gravity of the Dipper must be con- 

 siderably less than that of an Otter or a Beaver, and we 

 know that diving and remaining under water is not accom- 

 plished by these animals without great and continued exer- 

 tions. Accordingly Macgillivray, whose account of the Dip- 

 per is one of the most complete and perfect ever published, 

 observes (Naturalist, 1837, p. 108) : 



" I have seen it moving under water in situations where I 

 could observe it with certainty, and I readily perceived that 

 its actions were precisely similar to those of the Divers, 

 Mergansers, and Cormorants, which I have often watched 

 from an eminence as they pursued the shoals of Sand-eels 

 along the sandy shores of the Hebrides. It, in fact, flew 

 not merely using the wing from the carpal joint, but extend- 

 ing it considerably and employing its whole extent, just as 

 if moving in the air. The general direction of the body in 

 these circumstances is obliquely downwards ; and great force 

 is evidently used to counteract the effects of gravity, the 

 bird finding it difficult to keep itself at the bottom. Montagu 

 well describes the appearance which it presents under such 

 circumstances : ' In one or two instances, where we have 

 been able to perceive it under water, it appeared to tumble 

 about in a very extraordinary manner, with its head down- 

 wards, as if picking something ; and at the same time great 



