254 
CLASS IV. 
PALYTHOA. 
Polypidom in one extended patch, covered with 
cylindrical protuberances or papillae of more than a 
centimetre in height, and united to each other ; the 
cavities or cells insulated, almost longitudinally parti- 
tioned, and containing only one polypus. 
The Palythoas vary but little in their forms, and 
exhibit a mass composed of papillous protuberances 
five or fcix millimetres wide, and from one to one and 
a half centimetre high; these papillae are united and 
adhere together almost to their extremity, which is 
round, and pierced at the centre so as to allow the 
issue of the polypus. It is not improbable but that 
this opening may be the mouth of the animal ; which 
is contained in a large cell, having its partitions 
marked with projecting and longitudinal laminae, the 
number of which I have not been able to ascertain. 
The colour is an earthy grey. Such are the principal 
characters of the dried Palythoas. In the living state, 
that earthy colour does not exist, but brilliant hues 
then adorn this animated mass ; for I do not look 
upon these papillae as inert cells into which the po- 
lypi retire, but as forming part of the animal itself, 
as far more necessary, and far more connected with 
its existence, than are the shells of many testaceous 
Molluscas with theirs. 
These Polypidoms, scarce in the collections, are 
found in the Antilles. 
