Fig. 8.
Kinetoskias cyathus. (From Voy. Challenger, Atlantic: Wyv. Thomson.)
Fig. 10.
Scrupocellaria reptans. A. Creeping over seaweed, natural size; B. Front surface, magnified.
a, branched spine covering front of membranous area; b, avicularium; c, vibraculum.
C. Back surface; a, vibracular cell; b, vibraculum.
In Caberia ellisii the vibracular cells are very large. The vibracula, which are long and serrated, have been observed to move in unison like a double row of oars.
Case A 1, 2.
Section B. Flustrina.—In this group the colonies form leafy lamellæ, crusts, etc., in which the individual cells are typically in the form of oblong boxes with their front walls wholly or partly membranous. Flustra foliacea has already been described. |Case A 1.| In Flustra carbasea the fronds are formed of only one layer of cells, and not of two layers back to back as in F. foliacea. The fine specimen of Flustra nobilis from S. Africa is so called from the large size of its long hexagonal cells which form a honeycomb pattern clearly visible to the naked eye.
Case A 1.
In Flustra cribriformis(*) (Fig. 11), from Torres Straits, the fenestrated frond forms a beautiful spiral. Flustra florea, from S. Australia, grows in the form of branching tufts of narrow spiral fronds. Electra pilosa [dry and spirit specimens exhibited] (Fig. 12) forms a delicate silvery lace-work, encrusting shells and seaweeds (especially red algæ) on almost every shore. The long horny spine at the base of the membranous area of each cell gives the crust a pilose appearance. In Electra verticillata from West Africa, the cells form an elegant branched colony, the branches being composed of regular verticils of cells.
