In Auguft 1770, I found feveral of this kind of frefti-
water polype, which I kept for fome months, and found
that they fend forth 12 claws , when they are in perfection.
For a further defcription of this extraordinary animal,
with the remarkable experiments on its reproduction
when cut in pieces, I {hall refer the reader to a moft curious
treatife, wrote particularly by Mr. Abraham Trem-
bley, F. R. S. on this fubjecft ; and likewife in the introduction
to my Effay on Corallines, the reader will find a
fhort defcription of its properties; as alfo in my letter
to the Earl of Hillfborough, in the 57th Vol. of the Phi-
lofophical Tranfactions, upon the Actinia Sociata.
III. F L Ü S T R A , T H E S E A M A T T
Animal affixum, raro
tubulis radicalibus.
Stirps membranacea fo -
liacea, ex feriebus cellula-
rufn multifidis et diver-
gentibus coalita, quafi
context a.
Is an animal that grows on
other bodies, and fometimes,
but rarely, it adheres by little
radical tubes to them.
The ftem is a membranaceous
leaf-like fubftance, confifting
of many rows of cells united
together, which fpread out as
they grow, and divide into
many parts ; the whole fur-
face having the appearance of
being wove like a matt.
It fends forth through the
pitula
Cellulæ ringentes, capitula
Hydriformia fu n do
adnata exfer entes.
Ovaria : bullulee fupra
cellulas.
mouth-like openings o f its
cells, fuckers or feelers,
fhaped like the frefh-water polype
; thefe are fixt at the
bottom of each cell.
The ovaries appear to be the
pearl-like ftuds, which we
find at the tops of the cells.
This genus was formerly called Efchara, before Dr.
Linmeus changed it to Fluftra. The criticks find fault
with him for altering the old name \ for my part, I think
he has done it very properly. The name of Efchara fig-
nifying the cruft on the flefh that proceeds from the
wound of a burn, a term ufed in furgery, and therefore
improper : but Fluftra, being derived from tpAoof, teges,
a matt, is more defcfiptive of the appearance of thefe
fubftances, which look as if they were woven like matts,
and therefore much better adapted.
Befides it was necefl'ary to feparate the membranaceous
from the ftony fubftances, both of which were formerly
under the name of Efchara: otherwife we might as well
rank the foft, fpongy and flefhy fubftance, called Alcyo-
nium digitatum, or Dead-man s toes, as a Madrepora,
there being nothing but the difference of their component
parts that prevents it ; the Madrepora being ftony,,
and the Alcyonium fpongy.
i. Fluftra truncata.
Fluftra foliacea dicho-
to.ma, laciniis linearibus
truncatis, tubulis radicalibus
infiruEla.
Square-top’d Sea Matt.
This Sea Matt grows in a
fubdivided manner, with narrow
fquare-top’d leaves ; the
bafe is furnifhed with adhering
root-like tubes.
C 2 Fucus