A Monograph of the Fresh-water Polyzoa: Including All the Known Species, Both British and Foreign, Tema 28

adherent admit Alcyonella alimentary canal Allman already anatomy animal appearance Ascidian attached become Beneden bodies branches branchial British cænæcium cavity cell character cilia closely complete condition connected consists constitutes contained continuous corresponding Cristatella described detected disc distinct Dumortier ectocyst edit endocyst entire epistome examined existence extending external extremity fibres fluid Fredericella fresh-water Polyzoa genera genus Gervais gives Hist important internal latter layer Leidy lophophore Lophopus margin mass Mém membrane memoir minute mouth muscles Natural naturalists nearly observed occur organ orifice Original figures Paludicella passes Plumatella Plumatella repens Polype polypide Polyzoon portion present published relations repens represented resemblance retraction retractor Rösel seen separated sheath side space species specimens statoblasts stomach stones structure surface surrounding tentacula transparent transverse Trembley true tubes Tubularia tunic Tunicata walls whole young