CHAPTER Xn. 



THE GANNET'S anatomy. 



The Value of Anatomy to Systematists — The Gannet's Air 

 Cells — The Cellular Tissue next the Skin — The OEsophagus — 

 Trachea and Syrinx — Tongue — Eye — Brain — Ear — Oil-gland. 



The Value of Anatomy to Systematists. — In a monograph 

 of a single genus of birds, and still less of one species, 

 no writer can afford to neglect anatomy,* and that for 

 several reasons, of which not the least is that by 

 observing the organic structure of his subject, he will 

 best know where that bird's proper place is in any 



* It was a Scotchman, William Macgillivray, at that time little 

 known to fame, who first in Great Britain (1837) propounded a 

 scheme for the classification of birds by anatomy. Hitherto his 

 countrymen had been for the most part content with the system of 

 the celebrated Linnaeus, which divided all birds into six orders, 

 chiefly in accordance with the form of the bill and feet. The modifi- 

 cations of the mouth, throat, c»sophagus, proventriculus, stomach, and 

 intestines seemed to Macgillivray to tlirow more light upon the affinities 

 of the larger groups of birds than any external organs, which by 

 themselves form an artificial arrangement ; and here the Scotch 

 naturalist showed himself ahead of his time. In the preface to his 

 "History of British Birds" this is clearly stated: "After much 

 consideration," he says, " and after examining the digestive organs 

 in a great number of birds, belonging to nearly all the families, I 

 have resolved to adopt the intestinal canal as a central point of 

 reference" {t.c. Vol. I.); and he does this in his work, in the thorough 

 way which was his custom. 



