The Development of the Alligator 305 



the intestine (i) . 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 

 (i), which in this section might be called the 

 stomach, is a faiily 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 (vii), 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 apparently 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 myocoel 

 {myc) on the right side is somewhat exaggerated. 

 Figure 1 6/ is in the middle region of the embryo 

 where both splanchnopleure and somatopleure are 

 unfused. Owing chiefly to the unclosed condition 

 of the midgut {i) and to the increase in length of 



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