No. 3.] OESOPHAGEAL GLANDS OF URODELA. 



99 



of the larval Amblystoma, and in the case of Necturus I have 

 satisfied myself, by comparison of the actual objects, that the 

 structures are identical. 



The latest larva examined was 65 mm. in length. This 

 animal was apparently about to undergo metamorphosis, as the 

 stratified epithelium of the mouth had been replaced by ciliated. 

 The pyloric glands were fully developed, and the ordinary gas- 

 tric glands had assumed the appearance they present in the 

 adult. The anterior portion of the stomach, about a millimeter 

 in extent, was still ciliated, but the saccular glands of this 

 region had undergone considerable modification. One of these 

 is shown in Fig. 7. It 

 will be seen that the 

 base of the gland has 

 grown out into a num- 

 ber of short secondary 

 tubules, formed for the 

 most part of zymo- 

 genic cells, and the 

 gland now consists of a 

 large number of such 

 tubules, each similar in structure to an ordinary gastric gland, 

 opening into a large common cavity lined by transparent mucous 

 cells corresponding to the neck cells of an ordinary gland. In 

 short, the saccular gland of the embryo is being transformed 

 into an anterior oxyntic gland of the adult. 



Two of the most anterior glands in this larva were included 

 in the oesophagus. All were in full physiological activity and 

 were filled with zy.mogen granules. 



I have been unable to secure a specimen of Amblystoma 

 undergoing metamorphosis, or one that has just completed it, 

 and am therefore unable to state positively whether all the sac- 

 cular glands become transformed by subsequent branching into 

 anterior oxyntic glands, or some of them degenerate and dis- 

 appear. There is in the latest larva that I have examined no 

 evidence of changes of a degenerate nature, and I am there- 

 fore inclined to believe that the most anterior glands, as well as 

 the rest, are taken up into the stomach, and that the oesophagus 



FIG. 7. Oesophageal gland of 65 mm. larva. Ross obj. 

 IB in., Leitz ocular No. i. 



