100 POPULAR HISTORY OF THE AQUARIUM, 



as to expand his disc beyond it, and he does so, sometimes, 

 to the extent of three or four times the diameter of the 

 body. The disc, being very thin, is sometimes extended in 

 different directions, so as to vary considerably from a cir- 

 cular form, and has sometimes been described as loled. The 

 tentacles are very numerous and small ; they are arranged 

 in five or six rows ; the innermost rows are the largest and 

 least numerous ; they are generally erect ; the successive 

 rows declining more and more, till the outer row lies nearly 

 flat on the edge. Beginning at twelve tentacles in the 

 inner circle, the number in each circle doubles, so that the 

 whole would amount to between seven and eight hundred. 

 Those on the outer rim only form a short fringe of minute 

 feelers, not the sixteenth of an inch in length. From be- 

 tween each tentacle runs a radiating line to the centre, 

 which gives a beautiful starry radiation to the whole. The 

 colours of Actinia, or Sagartia bellis, are as follows. The 

 lower part is white ; a little higher, it becomes pink, which 

 gradually assumes a purple hue. The upper part of the 

 body and the disc are palely spotted. The surface of the 

 disc is brown, sometimes mottled with grey. The ten- 

 tacles partake the same colour, but are variegated with bands 

 of white or grey, and sometimes speckled. 



