CESOPHAGUS, STOMACH, AND INTESTINE 261 



-Oe 



D 



FIG. 210A. FIG. 210B. 



FIG. 210A. ALIMENTARY CANAL OF Siren lacertina. 



Oe, oesophagus, marked off from the stomach (M) by a constriction, f ; P, pyloric 

 region ; MD, small intestine ; ED, large intestine. 



FIG. 210B. ALIMENTARY CANAL OF Rana esculenta. 



0e,"cesophagus ; M , stomach ; Py, pyloric region ; Du, duodenum ; D, ileum ; f, 

 boundary between the latter and the large intestine (R] ; A, opening of the 

 rectum into the cloaca (Cl) ; Hb, urinary bladder ; Mz, spleen. 



In Elasmobranchs a finger-shaped rectal gland (processus digiti- 

 formis) opens into the anterior part of the rectum, and this perhaps 

 corresponds to the caecum of higher forms (see pp. 262, 266). Traces 



