ORDER ACTINOIDEA. A7 
Here belong the Actiniz and the Zoanthide, and a large part of coral 
animals. ‘The Zoanthide are closely related to one division of the 
coral-making Caryophyllacea—the family Gemmiporide. They 
spread a wide disk, with a somewhat convex centre, and some- 
times the margin of the disk, bearing the fringe of tentacles, becomes 
much reflexed by expansion, curving downward towards the base of 
the polyp, so as to appear like a cap over the extremity. ‘The tenta- 
-cles are short, and correspond each to a radiate line on the disk; and 
in some species I have found one of these rays to have a different 
colour and size from the others, evincing some peculiarity of function 
in the tentacle, corresponding, apparently, to the long finger-tentacle 
in some madrepores. The Gemmipores* resemble these in general 
form and in their fringe of short tentacles, but the disk is not striated. 
In another division of the Caryophyllia tribe—the Caryophyllide— 
the tentacles are much like those of the common Actinia; and in ex- 
ternal form we distinguish no important peculiarity, except that the 
disk containing the mouth becomes more prominent, when the animal 
is fully expanded, sometimes having nearly the shape of an oblong 
inverted cone. 
The polyps of the Astrza tribe of zoophytes have numerous unequal 
tentacles, and a flat or simply convex disk. The distinction between 
the Astrea and Caryophyllia tribes depends on a different mode of 
budding, as is pointed out in a following chapter. ‘The visceral 
lamelle in the Astras appear to retain their identity through the 
side tissues or walls of the polyp, and, in compound species, these 
lamelle may be traced by their secretions through the intermediate 
spaces between adjoining polyps. These characters are strongly 
marked in the coralla of the different animals, although not so appa- 
rent, as far as I have examined, in the recent Actinie ({) 48 and 76, 
fig. 34). 
43. The only variation from the Actinia type which we here notice 
is presented by the Fungie and other allied zoophytes. The Fungiet 
are the largest of known polyps, some species attaining a diameter of 
eighteen inches. The form of the animal, instead of being cylin- 
drical, as in the Actinia, is that of a large disk, an inch or two thick, 
circular or elliptical in outline, and either flat or convex above. A 
large oblong mouth occupies the centre, and from the mouth narrow 
ridges radiate, with regular intervals, to the circumference—a few 
* See plate 30, figure 4. T Plate 27, figure 1. t See plates 18 and 19. 
