NUTRITION IN THE ACTINIA. 89 



in the Actinia, spaces intervene between the coats 



of the stomach, and the skin 

 of the animal. As the sto- 

 mach is not a closed sac, 

 but is open below, these ca- 

 vities are, in fact, continuous 

 with that of the stomach : 

 they are divided by nume- 

 rous membranous partitions 

 passing vertically between 

 the skin, and the mem- 

 brane of the stomach, and giving support to that 

 organ. Fig. 257, representing a vertical section of 

 the Actinia coriacea, displays this internal struc- 

 ture. B is the base or disk, by which the animal 

 adheres to rocks : i is the section of the coriaceous 

 integument, showing its thickness : m is the central 

 aperture of the upper surface, which performs the 

 office of a mouth, leading to the stomach (s), of 

 which the lower orifice is open, and which is sus- 

 pended in the general cavity by means of vertical 

 partitions, of which the cut edges are seen below, 

 uniting at a central point (c), and passing between 

 the stomach and the integument. These muscular 

 partitions are connected above with three rows of 

 tentacula, of which the points are seen at t. These 

 tentacula are here represented as they appear 

 when retracted within the mouth ; ready, however, 

 to be protruded by the injection of water into their 

 cavities from the respective cells with which they 

 communicate. The ovaries (o) are seen attached 

 to the partition ; and the apertures in the lower 

 part of the stomach, by which they commimicate 

 with its cavity, may also be perceived. All these 



