34 CORALS AND CORAL ISLANDS. 
out of a common spherical cell, as ade out by Dr. Mobius in 
his careful microscopic investigations. The Actinia affording 
the results was the Urticina crassicornis, found in both Euro- 
pean and American seas. The actual size of the cell represent- 
ed in figure 6 is about a 5,000th of an inch. In fig. 7 the 
lasso-cell has already taken form but is folded on itself; in 8, 
there is a second infolding; 9 shows a return to a single fold, 
and further progress in the forming cell; and 10, the straight- 
ened lasso-cell. Thus the work of replenishing, throughout 
the body wherever lassos are used, is always going on. 
The radiating partitions or septa in the internal cavity 
of the polyp have along the outer free edge what looks like a 
slender white cord attached to it by a much convoluted or 
mesentery-like membrane; and this cord contains vast num- 
bers of lasso-cells radiately arranged. These white cords 
through the multiplied plaitings of the mesenteric membrane 
have great length; and they sometimes extend up through the 
stomach and pass out of the mouth; or they are extended in 
loops through the walls wherever they may happen to be torn. 
There are often also bunches of somewhat similar white cords 
full of lasso-cells appended to the septa, which are extended 
from the body through some natural orifices near the base of the 
Actinia (especially those of the Sargartia family). Gosse calls 
these cords Acontia. ‘They extend out usually two or three 
inches, and sometimes six inches, and thereby widen much the 
stinging range of an Actinia, both for the purposes of defence 
and attack. 
Gosse, in his “‘ British Sea-Anemones,” 
gives the results of 
some experiments with regard to the action of these lasso-cells 
(cnide), from which a few paragraphs may be here cited. 
“Tt has long been known, that a very slight contact with 
the tentacles of a polyp is sufficient to produce, in any minute 
