254 



C. M. CHILD. 



marked with radiating lines, each of which terminates distally 

 between the bases of two tentacles ; those lines are in reality 

 grooves and mark the lines of attachment of the mesenteries to 

 the aboral surface of the disc. It will be seen that a small area 



24 



in the center of the disc, indicated iirthe figure by stippling, is free 

 from these lines ; this represents that portion of the thin mem- 

 brane beneath which regeneration of the mesenteries has not yet 

 occurred. In the directive radius is situated a small opening, 

 the new mouth, which gradually elongates in the directive plane. 



