ROOM X.] NATURAL HISTORY* 45 
In the Windows are placed some large specimens of 
Snakes, as the Indian Rock Snake {Python), a large 
Rattle-Snake (< Crotalus ), the Mourning Snake {Coluber 
pullatus) and the Crimson-sided Snake {Coluber por- 
phyr locus'). 
In the Table Cases, in the centre of the room, are 
arranged the general collection of Radiated Animals. 
The Sea-Eggs are at once known from the Star-Fish 
by the body being covered with a hard shell, formed of 
numerous small pieces, placed on bands, and by their not 
possessing a radiated or stellar form. The shell is covered 
with moveable spines, which serve the purposes of locomo¬ 
tion, and also enable the animals to bury themselves in the 
sand when left on the beach by the retreating tide ; it is 
likewise pierced with rows of minute pores, through which 
are emitted small tentacula with dilated ends, by which 
they attach themselves to rocks and other marine bodies. 
The Sea-Eggs are divided into several groups, according 
to the shape of the body, and the position of the mouth 
and anal orifice. 
In the first group, Spatangus, (Case 1,) the shell is 
nearly heart-shaped, with an oval compressed mouth 
placed in the front part on the under side, and the other 
orifice on the hinder margin. The upper part of the shell 
has the pores arranged in five short bands, resembling 
the petals of a flower. The shells of this group are thin 
and brittle, and the mouth of the animal, destitute of 
teeth, is often surrounded by a series of tentacula. 
In the second group, the mouth is in the centre of the 
under part, and the other orifice placed in or beneath the 
hinder margin. In some of these the shells are thin, and 
the series of pores arranged in vertical bands, extending 
from the top of the shell to the mouth ; as in the genus 
Pchinolampas (Case 1). The genus Galerites (Case 3), 
is only found in the fossil state. 
In the Shield Echini the shell is very solid and thick, 
and supported, internally, by perpendicular columns, so 
that they are capable of resisting the action of the waves 
for a considerable time. The mouth is armed with jaws, 
inserted in five triangular spongy bones, and the pores are 
placed in five arched pairs of bands, forming a star on the 
upper part of the shells. Some of the species of this 
