G. FLUSTRA, 
49 
MAMMILLARY. 
25. Flustra mammillaris. Incrustation ; cells 
nearly flat, with two obtuse risings at the sides of their 
opening; colour brown.— Plate 1. fig. 6. a. B. 
On the marine plants of Australasia. 
SHAGGY. 
26. Flustra hirta. Incrustation; coriaceous and 
flat; cells rambling and ciliated. 
Greenland sea. 
SINGLE-TOOTHED. 
27. Flustra unident at a . Incrustation; cells cy- 
lindrical, long and large, placed in parallel lines at 
the side of each other, or in longitudinal lines ; open- 
ing as large as the cell, with a large tooth on one side 
of its base. 
Australasia. 
ITALIAN. 
28. Flustra Italica. Membranous incrustation ; 
cells oval, almost compressed ; openings very small, 
placed at their summit . 
Strait of Messina. 
SANDY. 
29. Flustra arenosa. Incrustation friable and yel- 
lowish ; cells simple, ranged nearly chequer-wise. 
European seas. 
THICK. (FOSSIL.) 
30. Flustra crassa. Very thick incrustation ; 
Cells short and round, with projecting partitions, the 
upper part depressed ; openings large and crescent- 
formed. 
On an oyster and other fossils found near Ghent. 
Cor. 
G 
