50 
CLASS I. — ORDER I. 
TESSELLATED. (FOSSIL.) 
31. Flustra tessellata. Incrustation, thick ; parti- 
tions rounded in the fore part; openings in front, small 
and nearly round ; top of the cells flat and thick, of 
an ivory white, and very shining. 
On the fossils of the chalk in the vicinity of Paris. 
CRETACEOUS. (FOSSIL,) 
32. Flustra cretacea. Thick incrustations, with 
long oval cells. 
On fossil shells in the vicinity of Plaisance, analo- 
gousto the MurexTritonis of our seas. 
RETICULAR. (FOSSIL.) 
33. Flustra reticulata. Rather thick, forming 
free expansions, celluliferous on both surfaces ; cells 
oval and long, the partitions very projecting ; openings 
middling in size, and rather transversal. 
In the sand near Valogne in France, with Bacu- 
lites and Beleraites. * 
BIFURCATED. (FOSSIL.) 
34. Flustra bifurcata. Foliaceous, dichotomous 
expansions, bifurcated at the summits, and garnished 
with hexagonal cells on both surfaces. 
At Grignon, and in a lime* stone at Cerithes. 
BOTTLE-SHAPED. (FOSSIL.) 
35. Flustra utricularis . Incrustation in very 
spreading expansions ; cells oval and a little flat- 
tened, larger at the back, with rather a small opening 
placed in front. 
