G. FLUSTRA. 49 



MAMMILLAE Y. 



25. Flustra tnammi/laris. 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 unidentata. 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 



