DEVELOPMENT OF REFLEX MECHANISMS 71 
in the first contraction are cross-hatched with simple oblique lines; these at first 
are at the upper end of the body (as in fig. 4), while in the second phase this move- 
ment is farther back (fig. 5). In figure 5 the myotomes involved in the second 
contraction at the beginning of the second phase are double cross-hatched. 
