NOTES ON THE DEVELOPMENT OF THE NEWT. 575 
front of the anus in a newly hatched larva. At this time it is 
seen to cccupy the normal position of the post-anal gut, being 
situated between the dorsal aorta and caudal vein. 
In the Frog we find a post-anal gut with a wide lumen 
behind the blastopore. The lumen gradually narrows towards 
the hind end, and loses itself in the indifferent tissues of the 
tail. Later the lumen is lost, and the post-anal gut becomes 
solid. 
Dr. Gasser gives an account of a post-anal gut in Alytes (8) 
like that of the Newt. The lumen of the alimentary canal is 
continued a very short way into it, and the rest forms a solid 
cord in the tail. There is no open neurenteric canal in 
Alytes. 
A post-anal gut of the same kind has been described by Mr. 
Shipley in Petromyzon (20). 
Tue Sromop#uM aAnpD Pirurrary Bopy. 
The stomodzeum developes as a solid ingrowth of the inner 
layer of the epiblast just in front of the anterior wall of the 
fore-gut (fig. 12). The lower part of the ingrowth fuses with 
the fore-gut (figs. 14, 8, 9) while the upper projects freely and 
forms the pituitary body (fig. 14). In fig. 8, which represents 
an oblique transverse section, the relations of the pituitary 
body to the stomodzum and fore-gut may be clearly seen. It 
grows upwards and applies itself closely to the infundibulum, 
curling round it (fig. 14) and forming an indentation in its 
floor (figs. 38, 37,36). The extreme end of the pituitary body 
is shown in fig. 38, where it is hardly distinguishable from the 
infundibulum. 
The stomodeum fuses with the fore-gut at a very early 
stage, but no actual perforation is formed until a short time 
after hatching. The region of fusion takes on gradually the 
shape of the adult mouth, becoming first elongated trans- 
versely, and then horseshoe shaped, with the concavity of the 
horseshoe directed backwards. The consequence is that, in 
transverse sections of late stages, the mouth appears to consist 
