87 (2) Flagellar organ absent; mouth opening present . 



.88 



88 (87) Frontal gland absent; ovary and testes folicular; male antrum with a side pocket but no gland cells around 



base of the seminal vesicle (Fig. 182); commensal in holothurians 



Genus Meara. 



Figure 182.— A/eora slichopL 



88 (57) Frontal gland well developed; compact testes and compact ovary; male antrum with many large gland cells 



around base of the seminal vesicle (Figs. 183, 184); free-living 



Genus Nemertoderma. 



Figure 183. — Semertoderma bathycula. 



Figure IM.—Nemertodenna rubra: a-sagillal reconslniction; b-sagittal section through pharynx; c-sagillal section of nuiie accessory organs. 



57 



