17 
retarding the movement of contents. The Sturgeon (Aci- 
penser Sturio) presents a differentiation between large and 
small intestine, marked by a valve resembling the pylorus. 
In Amphibia the alimentary canal is simple, without caecum, 
and usually short. 
Among Reptiles only the Land-turtles, some Ophidia, and 
some Saurians, like Lacerta, Iguana, Polychros, Draco, 
Chameleo, Seps, Scincus, possess a czecum. 
Nos. I-13. 
& WwW NS 
oon awn 
10 
aie 
12 
13 
fol. 
Salmo fontinalis, Brook Trout. Alimentary Tract. 
Rana catesbiana, Bull Frog. Alimentary Tract. 
Boa constrictor, Black Boa. Intestine. 
Boa constrictor, Black Boa. Intestine opened, showing spi- 
ral valve in interior. 
Chrysemys picta, Mud Turtle. Alimentary Tract. 
Alligator mississippiensis, Alligator. Alimentary Tract. 
Alligator mississippiensis, Alligator. Alimentary Tract. 
Alligator mississippiensis, Alligator. Alimentary Tract. 
Alligator mississippiensis, Alligator. Ileo-colon. 
Iguana tuberculata, Iguana. Ileo-colon. 
Iguana tuberculata, Iguana. [Ileo-colon. 
Iguana tuberculata, Iguana. Ileo-colon. 
Iguana tuberculata, Iguana. Ileo-colon. 
II. ILEO-COLIC JUNCTION IN BIRDS. 
In Birds the length of the intestine varies very much. It is 
short in species living on fruits and insects, long in those 
feeding on seeds, plants, and fish. Peculiar to Birds are 
the double ceca which are usually found. In the Passer- 
ine Birds, living on seeds and insects, the cecal pouches 
are commonly short and rudimentary, as they are also in 
some of the piscivorous divers, Alca, Larus, and Pelargus. 
They are very long in the Ostrich, in Rhea, Apteryx, and 
the Lamellirostra, who feed chiefly on plants. Some car- 
nivorous birds, as Corvus, Strix, etc., have fairly long ceca, 
although as a rule carnivorous forms have short pouches, 
whereas they are long in herbivorous birds. In some 
(Ostrich) the czeca contain a spiral valve. 
In place of the usual double pouch a single czcum is at 
