2 INTRODUCTORY OBSERVATIONS. 



often long, but are less expert at flying, and are with diffi- 

 culty raised. Others, again, the Herons, Bitterns, and Storks, 

 having very elongated legs, and very ample wings, are less 

 active, many of them searching quietly for their prey, or 

 remaining in a fixed position until it approaches them in 

 the water. 



The food of these birds is various, and their alimentary 

 canal is correspondingly modified. They mostly swallow the 

 objects fitted for affording them nourishment entire. Those 

 which live on worms, insects, small mollusca and Crustacea, 

 have the mouth and oesophagus narrow, and the stomach 

 muscular ; while those which prey on fishes, frogs, and other 

 reptiles, have a dilatable mouth, a very wide oesophagus, and 

 a membranous stomach. None of them are furnished with a 

 crop, and none are purely phytophagous, although several 

 approach in form and habits to the Gallinaceous birds. 



If among the Grallatores any birds represent, by analogy 

 or similitude of structure and habits, the Raptores, it must 

 be the Herons; among which are some, as the Adjutant 

 Stork, which differ little in their omnivorous propensities 

 from the Vultures. These birds differ from the rest in having 

 the oesophagus much wider, and in form and structure similar 

 to that of the fish-eating Palmipedes, the stomach in a degree 

 membranous, like that of the rapacious land birds, without 

 lateral muscles, or strong epithelium ; the intestine extremely 

 slender, and the anterior extremity of the large intestine, 

 or rectum, furnished with a lobe, or sac, but destitute of the 

 two lateral coeca which occur in most birds of all the families. 

 They form a group very clearly defined, although not uncon- 

 nected with others, and, if long legs and wading habits be 

 peculiarly characteristic of the Grallatores, they are certainly 

 entitled to typical pre-eminence. But there are various ways 

 of viewing birds, and analogies are never wanting to support 

 preconceived theories. Any of the other families might in 

 fact be assumed as equally typical. But supposing the Rap- 

 tores typical of the Aerial Land Birds, the Cantatores of the 

 Perching Land Birds, and the Divers, Guillemots, and other 

 allied species of the Natatorial Birds, the Herons seem to be 

 their analogues among the Grallatorial Birds. 



