Mr. Black wall's Remarks oti the Diving of Aquatic Birds. 25 



crater ; the wings are placed forward and out of the centi-e of 

 gravity for a purpose which shall be noticed hereafter; the 

 thighs quite at the podex, in order to facilitate diving ; and 

 the legs are flat, and as sharp backwards almost as the edo-e 

 of a knife, that in striking they may easily cut the water ; 

 while the feet are palmated, and broad for swimming, yet so 

 folded up when advanced forward to take a fresh stroke, as to 

 be full as narrow as the shank. The two exterior toes of the 

 feet are longest; the nails flat and broad, resembling the 

 human, which give strength and increase the power of swim- 

 ming. The foot, when expanded, is not at right angles to 

 the leg or body of the bird ; but the exterior part inclining 

 towards the head forms an acute angle with the body ; the in- 

 tention being not to give motion in the line of the legs them- 

 selves, but by the combined impulse of both in an interme- 

 diate line, the line of the body. 



" Most people know, that have observed at all, that the swim- 

 ming of birds is nothing more than a walking in the water, 

 where one foot succeeds the other as on the land ; yet no one, 

 as far as I am aware, has remarked that diving fowls, while 

 under water, impel and row themselves forward by a motion 

 of their wings, as well as by the impulse of their feet ; but 

 such is really the case, as any person may easily be convinced, 

 who will observe ducks when hunted by dogs in a clear pond. 

 Nor do I know that any one has given a reason why the wino-s 

 of diving fowls are placed so forward: doubtless, not for the 

 purpose of promoting their speed in flying, since that position- 

 certainly impedes it ; but probably for the increase of their 

 motion under water, by the use of four oars, instead of two ; 

 yet were the wings and feet nearer together, as in land-birds, 

 they would, when in action, rather hinder than assist one an- 

 other." 



Mr. White's description of the manner in which the Northern 

 Diver impels itself through the water by the agency of the 

 legs, which have an extent of motion enabling it to*alter its 

 course in any direction whatever with astonishing facility, is 

 applicable to diving-birds in general ; but it does not appear 

 that the wings are so uniformly employed to promote their 

 progress when submerged, as the statement of the natural 

 historian of Selborne would seem to imply. 



I may remark, in conclusion, that the action of the legs in 

 diving, so far from giving birds an impulse upward and for- 

 ward, as Montagu has affirmed, evidently tends rather to 

 propel them downward and forward, except when they pur- 

 pose to ascend, and then a change of action, adapted to the 

 accomplishment of the object to be attained, is instantly re- 

 ThirdSaies. Vol. 1. No. 1. My 1832. E 



