The Development of the Alligator 305 
the intestine (7). Under greater magnification it is 
seen to be made up of indefinite strings of cells; and 
its still wide opening into the intestine may be 
seen in more posterior sections. The intestine 
(4), which in this section might be called the 
stomach, is a fairly large cavity with the usual 
thick entodermic walls; it is supported by a com- 
paratively narrow mesentery. The body cavity 
on the side next this mesentery has the same thick 
lining that was noted in the region of the lungs. 
The convolutions of the thick peritoneal lining 
may easily be mistaken in places for parts of the 
enteron. The Wolffian bodies may be seen as two 
groups of tubules (wt) in their usual location. The 
heart is cut through the ventricle (vz), as has been 
said. The section being at right angles to the long 
axes of the villi-like growths of the myocardium, 
the depressions between these mesoblastic cords are 
seen as a number of small irregular areas, each one 
lined with its endocardium. The incompleteness 
of the body wall below the heart is appareutly due 
to an artificial break and not to a lack of fusion. 
The only point that need be mentioned in connec- 
tion with the structures of the dorsal part of the 
section is that the distinctness of the myoccel 
(myc) on the right side is somewhat exaggerated. 
Figure 16f is in the middle region of the embryo 
where both splanchnopleure and somatopleure are 
unfused. Owing chiefly to the unclosed condition 
of the midgut (z) and to the increase in length of 
20 
