84 



Mr. A. Willey. On the 

 FIG. 4. 



[May 22, 



JUh 



Copy from Rolph of a similar section through an older larva, showing the com- 

 mencing longitudinal downgrowths. 



E. Epidermis. 



\. Inner epithelium of the (future) atrial cavity. 



E%. Outer epithelium of same. 



U. Subcutaneous tissue. 

 Other letters as in fig. 3. 



FIG. 5. 



Copy from Rolph of a similar section showing the meeting together of the 

 " epipleura " in the ventral middle line. 



A. Atrium. E. Raphe. 

 Other letters as in figs. 3 and 4. 



