"Diagram of the metamorphosis of the free, tailed larva into the fixed Ascidian. A, stage of free-swimming…
"'Nurse' of Doliolum mulleri. I., Inhalant, E., exhalant aperture; C., ciliated band round pharynx (P.);…
"Sexual individual of Doliolum mulleri. G., gonads; B., gill-slits; I., Inhalant, E., exhalant aperture;…
"Diagram of Salpa africana. o.a., Oral aperture; d.t., dorsal tubercle; te., tentacle; g., ganglion;…