338 



COMPARATIVE ANATOMY 



Oe 



~t 



\--ED 



FIG. 248. FIG. 249. 



FIG. 248. ALIMENTARY CANAL OF Siren lacertina. 



ED, large intestine ; MD, small intestine ; Oe, oesophagus, marked off from the 

 stomach (M) by a constriction (t) ; P, pyloric region. 



FIG. 249. ALIMENTARY CANAL OF Rana escidenta. 



A, opening of the rectum into the cloaca (Cl) ; Z>, ileum ; Du, duodenum ; f 

 boundary between small and large intestine ; HB, urinary bladder ; Oe, 

 oesophagus ; M, stomach ; Mz, spleen ; Py, pyloric region ; R, rectum. 



Dipnoi a cloacal caecum is present (Fig. 247; cf. under Urino- 

 genital Organs). 



In all Fishes in which a cloaca is wanting, the anus is 

 anterior to the urinogenital aperture. 



