130 POPULAR HISTORY OF THE AQUARIUM. 



from foreign seas, which yet dwindle to insignificance com- 

 pared to the immense masses from which they have been 

 torn. Yet if we examine our own British species, it will 

 not be difficult to trace the line that leads from them to the 

 more complicated forms of their wonder-working brethren 

 in distant oceans. 



Caryophyllea Smithii. — (Plate III. fig. 2 to 7.) 



Some of the Actinicc are very fond of crawhng upon the 

 glass sides of a tank, so as to present their basal disc to 

 the observer. It is of an irregular circular form, and a 

 transparent whitish substance ; but from the centre may be 

 seen numerous opaque white threads radiating to the cir- 

 cumference. These threads must be the edges of folds or 

 plates running through the body of the animal lengthwise. 

 In the Actinia the plates, although more opaque, and con- 

 sequently more dense, are yet soft, and essentially composed 

 of the same substance with the other ])arts of the body. If 

 we cut the body across in any other part, so as to form 

 another disc, the same radiating white hues would appear, 

 indicating a continuation of the vertical plates. But if, in- 

 stead of being soft or gristly, these plates were hard and 

 bony, we sliould be presented with exactly what occurs in 



