ORGANS OF DIGESTION. 



319 



FlG. 111. 



disk is covered with long muscular tubular conical prehensile 

 tentacula, disposed irregularly, with minute terminal aper- 

 tures, striated with transverse muscular bands, and pro- 

 truded by the injection of water into them from below, like 

 the tubuliform feet of echinoderma. In the fungia actini- 

 formis (111. A. D.) the tentacula are very numerous, long, 

 brown-coloured, slender, sub-cylindrical, and terminated by 

 a yellow-coloured, dilated, perforated disk ; the general 

 surface of the polypus is yellowish-coloured with green 

 striae; the long, convoluted, white ovaries, like those of 

 actiniae, are protected between the vertical plates of the cal- 

 careous axis (111. D.) ; the flesh passes likewise over the 

 inferior surface of the axis which is concave, and laminated 

 on that part as above ; and when the animal is alarmed the 

 tentacula are withdrawn between the upper vertical lamellae, 

 the flesh shrinks downwards between these plates and is 

 found accumulated chiefly on the under concave laminated 

 surface of the axis. The tentacula are larger, fewer in num- 

 ber, more muscular, thick, and conical, in the fungia crassi- 

 tentaculata (111. B. C.) ; they rise from a yellowish-coloured 

 flesh covering the flat upper surface of the lamellated orbi- 

 cular axis (111. C.) ; they are formed like leeches, striated 

 transversely, of a brown colour, and terminate in a greenish- 



