88 BENSLEY. [VOL. II. 



down the oesophagus we find that, at the point where the cili- 

 ated epithelium is succeeded by the ordinary mucigenous epi- 

 thelium of the stomach, there is a gradual transition from the 

 compound oesophageal glands to the more simple tubular 

 glands of the stomach, the second type. The secreting cells 

 of the two kinds of gland differ markedly from one another. 

 Those of the gastric glands contain few zymogen granules of 

 small size, while those of the oesophageal glands are more or 

 less filled with very large granules, and the cells themselves 

 are larger. Further, the oesophageal glands yield an alkaline 

 secretion, the gastric glands an acid secretion. 



In Triton, again, there are two types of gland. At the 

 junction of oesophagus and stomach occur the anterior oxyntic 

 glands of Langley. The difference between these glands and 

 the other gastric glands (posterior oxyntic glands of Langley) 

 is not so marked. The former are more highly branched and 

 are separated from one another by a larger amount of connec- 

 tive tissue, but the differences in the size of the granules and 

 in the nature of the secretion, so conspicuous in the case of 

 the frog, are absent. 



In Proteus a new structure makes its appearance in the 

 shape of isolated sac-like glands occurring in the oesophagus. 

 These have been fully investigated by Oppel (u), who de- 

 scribes them as follows : " Die Driisen des Oesophagus haben 

 eine rundliche Form. Sie bestehen aus einem grossen Acinus. 

 Die Drusen sind zusammengesetzt aus einem Ausfuhrungs- 

 gang und dem secernierenden Theil. Ich spreche von einem 

 Ausfiihrungsgang, da sich die Zellen desselben von denen der 

 Schleimhautoberflache unterscheiden. Der Ausfiihrungsgang 

 besteht aus Zellen von annahernd cylindrischer Form, und zwar 

 ist die Grenze zwischen conischem und cylindrischem Epithel 

 stets eine scharfe. Eine besondere Eigenthiimlichkeit liegt in 

 der Uebergangsstelle von cliesen cylindrischen Zellen des Aus- 

 fiihrungsgangs zu den secernierenden Zellen. Dieselbe liegt 

 namlich nicht an der Stelle, an welcher die Erweiterung des 

 engen Ganges zum Acinus stattfindet, sondern die Cylinder- 

 zellen gehen noch ein Stuck weit in den Acinus hinein, um 

 clann rasch zu den niedrigeren secernierenden Zellen abzufallen. 



