PLATE IV. 
Fig. 1—Aetea anguina Linneus. Habit sketch, about natural size. 
Fig. 2.—A. anguina. Portion of a colony enlarged showing variations 
in height of the erect, tubular part (tu.) of the zomcia. Adherent 
(ad.) portion attached to the substratum like a stolon is part of the zowcium 
which rises at its anterior end into the ringed tubular portion (tu.). The 
polypide (pd.) can be seen inside several of the zowcia; when fully ex- 
panded it protrudes through the operculum (op.) at the summit of the tube. 
The zowcia are separated from each other by a septum (sep.) at the anterior 
end of each. X 30. 
Fig. 3—A. anguina. Part of a zowcium in which the polypide (pd.) 
is in a state of retraction; upper part of tubular portion broken 
away. Polypide retracted by contraction of retractor muscle fibres (mus.) 
attached to the wall of the adherent portion (ad.) of the zowcium. In the 
adherent portion the ovary (ov.) is visible. > 70. 
Fig. 4.—A. anguina. A single zoecium much enlarged showing position 
of owcium (0e.) just outside the aperture (ap.), below the operculum on 
the ventral side of the zowcium. Within the oecium is an ovum in early 
cleavage stage (emb.). X 70. 
Fig. 5.—Aetea truncata Landsborough. Portion of a colony enlarged to 
show variations in height of the erect, tubular portions (tu.), also length 
and slenderness of the adherent portions (ad.) of the zowcia. X 30. 
Fig. 6.—A. truncata. Habit sketch, about natural size. 
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