ROOM II.] NATURAL HISTORY. 57 
sponges greatly resemble the axes of the Gorgonice , in 
their chemical composition and organic structure, they 
nevertheless cannot be confidently pronounced to belong 
to the animal, rather than to the vegetable kingdom. 
In some, the skeleton, which alone can be shewn in the 
dry state, consists of a horny fibre, ( Spongia ,) in others it 
is formed of interwoven calcareous spicula, which greatly 
vary in their shape. In a few the spicula are formed of pure 
flint, and of sufficient hardness to scratch glass. 
The Tetliya , (Table 7,) differs from the sponges with 
siliceous spicula in being more or less globular, with all the 
spicula radiating from the centre, and in its outer surface 
being covered with a crust formed of minute calcareous 
globules. 
Table Case, No. 8, contains the Corallines, which 
were formerly considered as animals, and are now generally 
regarded as sea-weeds, differing from most of them in having 
a large quantity of calcareous matter in their composition. 
Many of them are furnished with small tubercles similar 
to the organs of fructification of Fuel and Marine Con - 
fervee, and are destitute of those cells on the surface which 
are always found in the corals. 
M. De Blainville has formed them into a group under 
the name of Pseudozoa, or false animals. Some are articu¬ 
lated, as Cor a lima, Jania, &c.; others are frondose, as 
Flabellaria, and marked with the zones of growth; their 
edge is generally very thin and reflexed, until they are 
hardened by the deposition of the calcareous particles in 
their substance. Others have a head formed, as in Peni - 
cillns , of a tuft of fibres, which are sometimes united into an 
umbrella-like head, asi n Acetabular ia; and one ( Nullipara , 
Lam.) is hard and stony, forming crusts, or variously 
shaped lobes or branches, on stones, shells and other marine 
bodies. 
ROOM II. 
The Table Cases in the Second and Third Rooms con¬ 
tain the collection of Radiated Animals, ( Centronics , 
Pallas,) so called from all the parts of their body and 
members being disposed in a radiated form, which often 
gives them the shape of the flowers of plants. 
The pores of the skin of some kinds, and the whole of 
d 3 
