PLATE III. 



Ascidia mentula Miill. (p. 75) 



FIG. 



1. Aperture of branchial sac. 



2. Central portion of ventral blood-channel, continued at x 



in fig. 3. a, vessel leading from mantle and appearing 

 to open into lateral vessel at b (repeated above and 

 below), and perhaps into net-work of vessels in space c. 

 d (repeated below), vessel leading from mantle to 

 branchial vessel e, and apparently opening into it. 



4. Heart, with blood-channel s leading from it. 



5. Endostyle ; anterior end. 



All the figures magnified. 



