INTRODUCTION. xxiii 
tissues, and in different regions of the body. They abound 
in the walls of the tentacles, in the marginal spherules (of 
Actinia proper), in the corrugated integument that sur- 
rounds the mouth, in the walls of the stomach, and in the 
epidermic mucus that is thrown off from these last-named 
parts on the stimulus of irritation. But there are certain 
special organs in which they are crowded to an extraor- 
dinary degree, and which, so for as I know, have no other 
function than that of being magazines of the cnida;. These 
organs arc of two kinds, which I have designated respec- 
tively as craspeda, and acontia. 
The Craspeda. The peritoneal membrane of the septa, 
having formed, by the contact of its two laminse, a kind of 
mesentery, separates again to inclose the ovary ; again 
unites into a second mesentery, the edge of which is greatly 
puckered, and thickened in the form of a cylindrical cord, 
closely resembling the bolt-rope of a ship’s sails, or still 
more the cording in the hem of a flounced garment. This 
marginal cord, bound throughout its length to the ovary, or 
to the septum, by a mesentery, I call the Craspedum 
(Plate XI. fig. 2). 
So far as my examinations have gone, the craspeda are 
found in all Actinaria, and for the most part in great 
profusion. In T. crassicornis, for instance, they constitute 
an inextricable tangle of white frilled cords, seen every- 
where below and behind the stomach, and protruding 
through every wound of the integuments. The thickness 
of the cord does not, as has been stated, “ increase from 
above downward.” Nor does it “terminate in the coats of 
the stomach if we gradually cut away the stomach, piece- 
meal, until the free edge has disappeared, we still find the 
craspeda bordering the mesenteries of the sep)ta, until the 
latter are lost at the point of their convergence in the centre 
of the floor of the visceral cavity. 
The craspedum, under pressure, displays the following 
elements. (1.) A clear, colourless, highly refractile sar- 
code, wdiich, under extreme pressure, has a tendency to 
draw out into strings, and long-tailed drops, like a thick oil 
on a wetted surface. (2.) Minute scattered granules, very 
irregular in shape. (3.) ]\Iulberry-like aggregations of 
granules, of a clear yellow hue, compactly built together, 
and firm, which have the appearance of being inclosed in a 
definite cell-wall. These are generally ovate, but are some- 
