73 
plexity of other portions of the intestinal system, to 
diversities of czeca, &c. Amongst birds nearly the 
same differences are observable. The organs of di- 
gestion are more simple amongst the carnivorous, 
more complex in the herbivorous orders. The crop 
is less developed in the carnivorous, more in the 
granivorous. The gizzard possesses its full powers 
of muscular structure and horny lining only in the 
granivorous: with some exceptions, however, de- 
pendent on climate and food, as in the differences 
observed by Home in the African and American 
ostrich: which demonstrate that a different condi- 
tion might have existed, had it suited the plan or 
been accordant to the will of the great Ordainer. 
“The form of the stomach in amphibia is usually 
simple:” but in turtles the cesophagus is furnished 
with horny points, directed backward, and serving 
to prevent the escape of food. Home found in the 
eft a croplike dilatation of the cesophagus. He has 
noticed the thickness of muscular membrane in the 
stomach of a turtle, (testudo mydas,) living wholly 
on vegetables: and in the stomach of the siren, in 
which the intestine is also found to contain little 
pebbles, which assist in the trituration of food 4.” 
The digestion, however, is slow, although the sto- 
mach is less complex than that of birds, and the ali- 
mentary canal comparatively shorter. To this, how- 
ever, the coldness of the blood may contribute. It 
probably is the cause, contributing to their power 
“4 The stomach of a crocodile was observed by Home to bear 
great resemblance to that of birds of prey. 
