AN alcyonarian coral, Alcyonium (nat. size). 
the parts of the stock may he compared with the parts of a feather, the whole 
being bilaterally symmetrical, and the single polyps being carried on the leaf-like 
lateral appendages of the stem. The sexual animals, which are provided with all 
the organs necessary for a polyp, take in the food and reproduce themselves. The 
other less perfect brethren, called zooids, although more or less resembling these, 
512 CCELENTERA TES. 
common trunk. The foot swells out like an onion and becomes transparent, 
curves, and sinks into the stand; and the stock, which during its period of 
inactivity lay prone on the ground, assumes an erect position. In these sea-pens 
