No. 2.] ENTERON OF AMERICAN GANOIDS. 415 



occur in them during digestion and hunger. His observations 

 were made upon certain Amphibia and Reptiles. 



From the study of mitosis of the epithelial cells, Bizzozero 

 (6) concluded that the cells did not live and die in the place 

 where they originally arose, but that by degrees the deeper- 

 lying cells of the epithelium reached the free surface in a 

 manner precisely comparable to that which takes place in the 

 epidermal cells of the skin. In certain glands which had at- 

 tained their full development he found numerous nuclear fig- 

 ures, premonitors of active cell multiplication. These newly- 

 formed cells, he says, gradually replace the epithelial cells of 

 the free surface of the stomach, which, in certain animals, is in 

 the highest degree desquamous. In a more recent paper (7), 

 in which he examined the enteric glands and epithelium of the 

 mouse, he arrived at the same conclusion as above, namely, 

 that in the mouse, as in the rabbit, the gland epithelium is 

 gradually transformed into the surface epithelium of the mu- 

 cous membrane. 



Pilliet (49), in a paper on the evolution of the glandular cells 

 of the stomach, says that the gastric glands may assume very 

 different appearances, and that by noting the form and struc- 

 ture of the glandular cells at various points of the gastric fol- 

 licles he has tried to form a general idea, by studying the cells 

 from their appearance to their death, where each of the differ- 

 ent conditions were to be fixed in chronological order, and to 

 indicate the particular age to which it corresponds in the life 

 of the cell. He reaches the same conclusion as Bizzozero in 

 regard to the gradual metamorphosis of the glandular into sur- 

 face epithelial cells. 



Other writers on this subject might be cited, but enough 

 has already been said to indicate something of the nature of 

 the work already done, and the forms which have been studied. 

 Comparatively little has been done on the enteron of some of 

 the lower or more generalized forms. Among the fishes or 

 fish-like vertebrates very little attention has been given to that 

 old and interesting group, the Ganoids. Indeed, in the litera- 

 ture that I have been able to examine, only the most meager 

 references are made touching the morphology of the enteric 



