1*28 Observations on il<< 



are capable of being arranged into groups, of which at least twenty, 

 indicative of as many orders or families, might be enumerated. — 

 Thus : 



1. (Esophagus very wide, of nearly uniform diameter; stomach 

 large, membranous, with separate muscular fasciculi ; intestine short 

 and slender ; cceca rather long, narrow below, dilated towards the 

 extremity ; rectum with a large dilatation. Owls. 



2. (Esophagus very wide, dilated on the neck ; stomach large, mem- 

 branous, its fasciculi not distinct ; intestine slender ; cceca extreme- 

 ly small, cylindrical. Eagles and Hawks. 



3. (Esophagus wide, nearly uniform ; stomach large, membranous, 

 with large fasciculi ; intestme short ; cceca small. Kingsfishers. 



4. (Esophagus extremely large, of uniform diameter ; stomach 

 very small, rather membranous than muscular, but with a cuticular 

 lining ; intestine short ; two small cylindrical cceca. Gulls. 



5. (Esophagus extremely long and wide, of uniform diameter ; 

 stomach small and membranous ; intestine long and very narrow ; 

 no cceca, but in place of them a dilatation of the rectum projecting 

 beyond the insertion of the small intestine. Herons. 



6. (Esophagus long, narrow, of nearly uniform diameter; stomach 

 a powerful gizzard, with two strong, two-tendoned muscles, a por- 

 tion of one of which covering the fundus has its insertions below the 

 central tendon : intestine long and wide; cceca long, nearly cylin- 

 drical. Swans, Geese, Ducks. 



7- (Esophagus rather narrow ; a large crop ; stomach a powerful 

 gizzard ; intestine rather long and wide ; cceca about half the length 

 of the intestine, of great capacity, and having their mucous coat ele- 

 vated into longitudinal ridges. Grous, Partridges, Pheasants. 



8. (Esophagus rather narrow, but dilated into a large crop ; sto- 

 mach a powerful gizzard ; intestine long, of moderate width ; cceca 

 extremely small. Pigeons. 



In this manner, giving more detailed characters, and including 

 structural differences (such as the longitudinal rugee in the rectum 

 of ducks, the villous plicas in the cceca of grous, the smoothness, ru- 

 gosity, or scission, of the cuticular lining of gizzards, the forms of 

 the proventricular glandules, the modifications of the crop, which is 

 muscular in eagles, perfectly membranous in some conirostres, glan- 

 dular in grous, in the crossbill curved to the right so as to pass be- 

 hind and almost encircle the neck, the arrangement of the horny 

 papillae of the mouth and fauces, the number of salivary glands, 

 and the varieties presented by the tongue and bill,) I am persuad- 

 ed from experience, that not only might birds be grouped according 



