138 ECHINODERMATA. 



ininent common attributes pervade the whole, or that there is a common 

 resemblance among them. 



Externally, there is scarcely enough to establish affinity. 



The Holotlmria seldom shews its real form, and scarcely betrays any 

 portion of its genuine nature. The aspect of the Asterias does not bear 

 it the most remote resemblance ; and alike distant is that of the Echimix. 

 Did we descend to some others, usually included in the group, some 

 might say it was in quest of discrepancies. 



Again, where is there any correspondence in the organic struc- 

 ture of the others, with the beautiful arborescence of the Holothm-ia ' 

 where the curious tufts, or tubuli, or the madreporiform tubercles of the 

 Asterias or Ophiura ? Can any parallel be shewn with the extraordi- 

 nary reproductions of the former, so profoundly illustrative of Nature's 

 surprising energies to restore that perfection appointed for the works of 

 the Omnipotent. 



Nevertheless, something may be discovered to compensate all this ; 

 something to prove that kindred which is slowly disclosed to the scienti- 

 fic student, and such as some anatomists think they have found. 



Many sacrifices must be made for concentration, for order, and 

 brevity. 



A nameless charm attends regularity ; of itself, it facilitates labour, 

 and leads to the easier diffusion of knowledge. 



Our acquaintance with the group, we must also admit, is as yet 

 only in progress. Many additional and interesting facts evidently re- 

 main for its further embellishment. 



