74 
ROOM XI. 
Nat. Hist. 
round a cylindrical stem; and in a third genus( Lunulites ) 
the cell is thicker, and forms a cup-shaped disc, which 
is attached to sand or stone in its young, and free in its 
adult state. 
In the Cellarise (Cellar ia) the cells are placed in a 
quincuncial band round the joints of a cylindrical, forked 
coral, which is attached by fibrous tubular roots. 
In the family of Crissiae the cells are placed in longi¬ 
tudinal rows, opening on one side of a forked, fiat, sub- 
articulated, branchy coral, attached by tubular fibres. 
In four genera (Crissia, Chanda , Achamarcliis , and 
Bicellaria ) the cells are placed alternately, in two rows, 
their characters depending on the different forms of the 
cells. In another genus ( Gemmicellaria ) the cells are 
equally disposed in two rows ; they are opposite, and 
together form an ovate joint. In the Tricellariae ( Tri - 
cellaria) the cells are disposed in three rows, whilst in 
others (Eucratea, Catenicella , and Menipea) the cells 
are placed one above the other, in a single unilateral 
series; these genera differing in the position of the 
mouth of the cells. 
The Polypiaria, which are characterized by the 
horny nature of their coral, are also peculiar for the 
cells which the animals inhabit being united together 
o o 
by a common tube, and by their being also formed with 
external vesicles, which are usually considered as ovaria. 
According to the observations of Cavolini, Thompson, 
and others, the structure of the animals of these corals is 
much more complicated than might have been ex¬ 
pected. 
The Tubulariae are known immediately amongst 
these corals by the long, tubular, cylindrical shape of 
their cells. They are to be distinguished from the 
eggs of the marine Mollusca, with which they have been 
confounded by Esper, w r ho has even figured the Byssus 
of the common Muscle as a species of this genus, 
under the name of Tubularia splachna. 
The Anguinariae and Tibianse are allied to the Tubu- 
larias, but they require to be further examined. 
In 
