are so tenacious of life, as to be incapable of destruction 
by mutilation. When a bead is severed from a body, th® 
latter acquires a new head, and the head a new body. 1 he 
head, or even the whole body, of one may be grafted on 
the body of another; or they may be divided into a multitm ® 
of parts and each will become a new body and a perfec 
animal. They mav even be turned inside out, or slit up an 
extended as a membrane, without much apparent injury- 
Per damna, per ctedes, ab ipso 
Dncit opes animunnpie ferro. 
When these experiments were first made public, they ex- 
cited, as they well might, the wonder of the world, nor do 
they now cease to astonish us, though made familiar 
Undine a place in most elementary works on Natural IlistorV 
and Natural Theology. Though'the polypes of the sheathe" 
or horny genera are incapable of undergoing such reniar 
able changes, yet the same disposition pervades the whole 
order. If for instance, the. Sea Oak (Sertularia pumila) oT 
the Great-tooth Coralline (S. polyzonias) he allowed ^ 
remain in impure water for a few days, their heads anil ten 
taenia will frequently drop off and the polypes shrink into > 1 
celis: but, afterwards if the water be frequently renewed, 
new head and ten taenia will soon be formed. At 
new parts differ in colour from the older portions, but tb 
difference in a very short time is entirely lost, although t u _ 
new tentacula are rarely equal in number to the old ones- 
a circumstance that explains the variety assigned by 
authors to the same species. In the Lnome.cka gciiiculata . * 
instance, I have counted in different specimens, 11, 19, 20 "r 
to 29 tentacula, so that no reliance can be placed on them 1 
determining the species. 
In their actions, these animals are comparatively slugg 19 ^ 
and in structure present, perhaps, the lowest iorni 
organized animal existence. When examined under * 
croscope, not a single fibre is discovered by which 
various actions can be supposed to be performed ; 
they appear to be composed entirely of minute distinct g* * 
ules, each of which seems to possess a power of indepond ^ 
vitality. The impressions which produce the motions ^ 
the tentacula and body appear to be communicated > r {g 
grannie to granule chiefly by contact. Tbe animal seen’® 
be a simple granular pulp; into which a central depres-^ 
is formed, which performs the office of a stomach, the 
ment being conveyed through the mass by imbibition, atl .j. 
refuse or excrementary part ejected through the same 
by which it is taken in. That the nutriment is conveys 
imbibition appears from the fact, that the colour n 
