72 POPULAR HISTORY OF THE AQUARIUM. 



and connecting the stomach with the interior of the poljpe, 

 the vibrating cilia covering every part of the inner lining, 

 the current of globules passing up and down along the pel- 

 lucid skin, and the curiously arranged coral-shaped spicula, 

 not unlike those of more decidedly spongoid bodies, are all 

 admirably and minutely described in the ' Naturalist's Ram- 

 bles on the Devonshire Coast/ As, in nature, the polypes 

 on a mass are never all exserted at the same time, we have 

 shown in one part of the figure (Plate V. fig. 1) the polj^es 

 fully exserted ; in another part some of them partially with- 

 drawn, others only showing the starlike petals ; and in other 

 parts of the specimen its appearance when the polypes are 

 withdrawn and the edges of the cells closed over them. 



Mr. Gosse, speaking of Alci/onimn, says, "Darkness is 

 more essential to its comfort than constant immersion. It 

 is more careless of exposure to air than of exposure to light. 

 The size and development of the masses are in proportion 

 to the obscurity of their residence. Even in these cavernous 

 recesses we only see half-grown specimens, and those con- 

 sisting of one or two lobes. When left by the tide these 

 hang down to a great length, the base shrunk to a slender, 

 skinny column, with a white fleshy lump at the tip, from 

 which depends a large drop of clear water ; but no sooner 



