ORDER ACTINOIDEA. 35 
vals, and thus a degree of uniformity obtains between the young and 
adult individuals, which is indicated in their coralla. 
26. The process of digestion appears to be extremely simple. The 
food is retained for a while in the stomach, and there acted upon by 
the gastric juice supplied from its walls, after which the refuse matter 
is ejected by the mouth. ‘The farther change to chyle probably takes 
place below in the visceral cavity, where a part of the nutrient fluid 
is absorbed, while another portion is distributed for assimilation 
throughout the various cavities, lacunes, or pores in the tissues of the 
animal. ‘Thus the processes of aeration and assimilation go on toge- 
ther throughout the whole structure of the Actinia, and there is a 
water-and-chyle circulation, nearly in the same manner as we have 
described with regard to the Hydroidea. No proper circulating fluid 
independent of this, and no branchiz, have been observed in these 
animals. Whether there are any excrementary secretions attending 
this assimilating process, as in other animals, has not been directly 
proved. Yet it is probable that the tissues about the visceral cavity, 
among their many functions, include the means of performing this 
part in the economy of the animal; and the waters expelled, in 
different ways, by the polyp, may carry off such secretions. It is 
remarkable, that while the biliary glands are of unusual size in the 
lower animals generally, in the Actiniw they are wanting; and this 
is no doubt connected with the fact that these animals are bathed so 
freely inside and out by the sea-water, which renders special organs 
unnecessary. If the above supposition be true, it is not proper to 
consider the mouth of a polyp as alone the only passage for the ex- 
crements. It ejects the refuse indigestible matters from the stomach, 
but only in part the proper excrements of the animal. 
The Actinie receive almost any animal food that falls in their way. 
Crabs, molluscs, the smaller fish, and other marine animals, are their 
common prey. ‘They have been seen with a large bivalve in their 
stomachs, from which the animal had been removed by their powerful 
gastric solvents. 
27. The function of reproduction belongs to the visceral lamelle 
(§ 25), part of which are spermatic and part ovarian. 
The spermatic lamellw are distinguished by being margined by 
a white capillary cord. This cord is much convoluted, and is at- 
tached to the lamelle by a thin and extensile membrane, which has 
a mesentery-like appearance.* The quantity of these cords in an 
* Similar to figures 35, 3c, 37, plate 30. 
