aA ZOOPHYTES. 
noidea.* We have nothing to add on the processes of digestion and 
circulation in these animals, in addition to what has been already 
presented, in our remarks on the Actinia and Palythoa. Nothing 
like branchiz were observed in the ‘Tubipore examined. 
General characteristics of the animals above described. 
38. The species described in the preceding pages, have been 
selected from the most widely-separated groups among the Acti- 
noidea, and are types of important divisions. ‘The points of agree- 
ment constitute the characteristics of this order, and may be here 
enumerated. 
1. The Actinoid polyp contains a large cul-de-sac visceral cavity, 
divided radiately into compartments by fleshy lamellae, and a stomach 
suspended in it beneath the centre of the disk. Several lamelle 
are united by their inner margins to the stomach, and aid, by their 
muscular action, in the expansion of the stomach and the expansion 
and contraction of the whole animal. 
2. The stomach communicates below with the visceral cavity, 
through an opening which may be closed by muscles. Its walls are 
muscular, and the organ admits of great dilatation, or may be con- 
tracted, at the will of the animal, to a slender tube. 
3. Digestion takes place in the stomach; and thence, after exclud- 
ing the refuse matter by the mouth, the results of digestion pass into 
the visceral cavity, to be aerated and elaborated through the air in 
both the external and the admitted waters, at the same time that these 
fluids are distributed, by an imperfect circulation, throughout the 
animal, and assimilated wherever needed for changes in progress. It 
is probable that excretions take place through the sides of the polyp, 
and by the waters which the animal ejects elsewhere on contraction. 
4. Reproductive functions reside in the visceral lamelle, part of 
which are spermatic and part ovarian. All of these lamellé are thus 
genital, excepting probably the upper portions of the larger lamelle, 
which are attached to the stomach, and in this part are muscular. 
The testes or spermatic organs have the form of white convoluted 
cords, and are attached to the margin of the lamella. The ovarian 
* This has been observed in certain species of the tribe, by Professor Grant and Milne 
Edwards.—For an interesting account of the developement of the ova, see a paper by Dr. 
Grant, in Jameson’s Edinburgh New Philosophical Journal, vol. i. p. 152; and also on 
the general structure and reproduction of the Aleyqnida, a memoir by Milne Edwards, in 
the Annales des Sci. Nat., 2d ser., iv. (1835), p. 321. 
