COMMON GANNET. 



65 



Ganiiet is a bird full of life and vigor, and this character is also strongly exhibited by the young, even at a 

 very early age, thus as remarked elswhere, I found that when newly hatched they were so hardy as to with- 

 stauil the cold of a rainy night without shelter, reviving when warmth was applied to them. On the other 

 hand as related at length in Vol. I of Contributions to Science, I found that the adults of Cory's Gannet were 

 weakly, and that the young were so very tender that they could not withstand a few degrees of cold, where- 

 as exposure for a few moments to the rays of the sun was also detrimental to them, specimens dying very 

 (juickly when placed in the full glare of the sunlight. 



What bettor illustration can we have of the care that Nature, our common mother, exercises over her 

 offsprings than this ? Operating through her mysterious laws, she hastens to supply the debilitated gan- 

 net under the burning tropical sun with a warm covering of down, while the more hardy gannet of the boreal 

 clime must endure the cold, simply because it can do so without absolutely perishing. In the north a sur- 

 vival of tlie fittest has produced a hardy, long-enduring species, by simply withholding clothing at a critical 

 period of the bird's life; thus allowing the weaklings to perish that the species may survive. In the south 

 an opposite law has attained a similar result; species have been evolved and perpetuated by the weakening 

 of offsprings, and consequently of adults. 



Fig. 12 



Young oftiik ('o.mmox (Janxet. Sfi.A kassaxa. two days old. taken on T.ird 1! rk. (!uH ■ fSt. ],aw- 

 rence, July 4th., Is?:!. 



Notes on Sula fiber. Booby Gaxxet. The trachea is simjilo, without ililatati>>ii. uinl is rounded f^r 

 at least the lower half, but is slightly enlarged at the inferior larynx. 



The sterno trachealis is comparatively slender and has its origin about .-V) above the larynx, see rig. 1 I 

 C, s, m being the trachea and b the bninc-hial tube. There is a thin, stap-like. brnnchialis muscle arising 



