75 
In some genera the cells are either urceolate, or bell¬ 
shaped, and pedicelled ; in the Campanulariae, the stem 
is simple and creeping; in the Laomediae, it is arbo¬ 
rescent. 
In the next group the stems are fistulous and branchy, 
but the cells are cylindrical, and placed in an unilateral 
series. In some ( Plumularia ) the cells are placed in a 
continued, in others ( Sertularia ) in an interrupted unila¬ 
teral series, whilst in a third genus ( Amatea ) they are 
disposed in a continued spiral line. The Biseriariae 
and Idiae have two rows of cells, placed on one side of 
the stem. 
In the Sertulariadse the cells are small, sessile, and 
dentiform, placed on the side of the branches. In 
most, as the true Sertulariae, the cells are subalternate. 
The Idiae only differ by the cells being placed rather 
more on one side than the other. The Dynamense 
are like the Sertulariae, but the cells are nearly opposite, 
so as to be placed in pairs. In one genus ( Pasythoa ) 
the cells are in pairs, separated from each other by a 
long stem, and in another ( Liriozoa ) they are in groups 
of three, similarly separated. 
In the Antennulariae the cells are very small, and placed 
in whorls round the fistulous jointed stem. 
The Cymodoceae appear to be only Sertulariae which 
have lost their cells. 
The last group of these kinds of Corals, the Flu- 
viatile Folypiaria, are characterized by their tentacula 
being numerous, long, simple, and retractile, and ex¬ 
panded in the form of a horse-shoe. They are in¬ 
closed in a long, tubular, horny sheath. This division 
includes two well-known corals, both found commonly 
in England, the Alcyonellae, in which the coral forms a 
globular mass, composed of numerous hexagonal tubes 
placed side by side, and the Plumatellee, in which the 
tubes are solitary, or united in a creeping group. It 
is probable that the Plumatellae may be only the young 
of the former. 
The Cases No. 13—16 contain the Zoophytes, so 
called 
ROOM XI. 
Nat. Hist, 
