128 Observations on the 
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 ; coeca 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 ; coeca extreme- 
ly small, cylindrical. Eagles and Hawks. 
3. (Esophagus wide, nearly uniform ; stomach large, membranous, 
with large fasciculi ; intestine 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 coeca. Gulls. 
5. (Esophagus extremely long and wide, of uniform diameter ; 
stomach small and membranous ; intestine long and very narrow ; 
no coeca, 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 ; coeca long, nearly cylin- 
drical. Swans, Geese, Ducks. 
7. (Esophagus rather narrow ; a large crop ; stomach a powerful 
gizzard ; intestine rather long and wide ; coeca 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 ; coeca 
extremely small. Pigeons. 
In this manner, giving more detailed characters, and including 
structural differences (such as the longitudinal rugae in the rectum 
of ducks, the villous plicae in the coeca 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 
