252 



HARDWICKE'S SCIENCE-GOSSIP. 



length of the bird is from thirty to thirty-three 

 inches. 



Having terminated our minute specification of 

 the most remarkable features appertaining to the 

 Great Northern Diver, we now proceed to enume- 

 rate and discuss tliree most important particulars 

 that present themselves to view upon the contem- 

 plation of the habits, mode of living, &c., of this 

 bird. 



(1.) It is an able and dexterous diver. With 

 respect to this circumstance, it may be observed, 

 that the sharp, conical bill, succeeded by the com- 



powerful muscles, which minister to the movements 

 of the wings. Great power is thereby imparted to 

 these instruments of progression, enabling the bird 

 to battle effectively with the air. It must always 

 be remembered, moreover, that the flying capa- 

 bilities of a bird are most accurately measured by 

 taking into consideration the power and extent of 

 the particular muscles now specified, rather than 

 by regarding the development of the wings alone. 

 Thus, for example, although the sternum in such 

 birds as the swallow, the swift, or the sand-martin, 

 is not particularly remarkable in respect of size, yet 



-- J"- 



Fig. 171. Great Ncrtlicni Diver {Culi/>n/jus gldcialis). 



paratively narrow and elongated neck and body, 

 conjoined with the short wings and suitably-placed 

 web feet, must powerfully contribute to the produc- 

 tion thereof. The immense expanse of chest pro- 

 bably also enables the bird to take a deep breath 

 immediately before diving, so as to obviate the 

 possibility of suiTocation while traversing the watery 

 regions. Moreover, it is worthy of observation 

 that the outline of its body is not (like the sea- 

 swallow, frigate-bird, &c.) broken up or diversified 

 by outlying feathers, but presents a smooth and 

 well-rounded surface to the spectator's eye. 



(2.) It flies strongly and rapidly. The immensely 

 developed sternum in tiie Great Northern Diver 

 furnishes a steadfast fulcrum for the attachment of 



the length, narrowness, and pointedness of the 

 wings, conjoined with the lightness and hollowness 

 of their bodies, insure an exceedingly rapid flight. 

 On the other hand, the body of the Great Northern 

 Diver is comparatively heavy, and the wings thereof 

 short and broad. These disadvantages, however, 

 arc amply compensated for by the possession of an 

 extensively developed breast-bone, which also (as 

 aforesaid) furnishes valuable assistance in the oper- 

 ation of diving. 



(3.) Its" home is in the Arctic regions. The 

 powerful aerial apparatus indicated by the immense 

 development of sternum in our bird is also iu valu- 

 able in the way of generating a vast amount of 

 animal heat'. It is a fact well known to animal 



