"\ 



Plate V. 



a: latticed rod supporting the posterior ventral arms. 



b: branch passing downwards along the ventral surface. 



c: branch running on the ventral surface towards its middle-line. 



d: branch passing downwards on the dorsal surface. 



e; branch passing forwards on the dorsal surface supporting the anterior arms. 



f: dorsal main branch, 



m : mouth. 



n: anus. 



oe-, oesophagus. 



p: water-pore. 



r: intestinal sac. 



st: stomach. 

 Fig. 82. Pluteus at the end of its first developmental stage, seen from the ventral surface. Drawn 



from a living specimen. 

 » 83. The same Pluteus. Side view. 

 B 84. The same Pluteus seen from the dorsal surface. 

 B 85. Side view of another Pluteus. The basal portions only of the posterior ventral arms are 



drawn. 



N. B. The cilia are generally omitted in the figures. The measurements are given in the 

 text. 



