ACTINIA. 245 



nation it is found to be distinct. It is only about half a 

 inch in diameter, and rather less in height. It is olive-green, 

 with snow-white stripes. The tentacula are numerous. 

 Dr. Johnston gives the following interesting account of it : 

 "This small but exceedingly pretty species has often in- 

 terested us in observing its habits. It occupies a hole 

 fitted to the size of its body, in our shelving, soft, slaty 

 rocks, where, when covered with water, it expands into a 

 wide circle, its oral disc and tentacula raising them scarcely 

 above the level of its habitation. Thus the Actinia retains 

 itself unbosomed, as if proud to display the beauty that its 

 Author has given it ; but should, perchance, a rude hand or 

 foe touch or ruffle the tentacula, then doth the creature 

 instantly shrink and withdraw within itself and its furrow, 

 until it has become nearly undistinguishable. The deserted 

 holes bored by the Pholas is a favourite retreat for this 

 Actinia, hence the specific name Troglodytes," suggested by 

 Mr. Price, in reference to the little classical people of that 

 name, said to live in dens and caves near the Arabian Gulf. 



8. ACTINIA ALBA, Cocks. 



Hab. Coast of Cornwall, in the crevices of rocks, W. P. 

 Cocks. 



This is minute, half an inch in diameter when expanded ; 



