ASTERIAS. 87 



CHAPTER II. 



ASTERIAS— THE SEA STAR. 



Various authors having devoted considerable attention to the his- 

 tory of the tribe comprehended under this name, or known as SteUerides, 

 I propose to Umit the present chapter to a few general observations on 

 certain species, which there is seldom much difficulty in obtainmg. 



Though the whole were included by earUer naturahsts in a single 

 genus, known as the Asterias or Sea Star, a name sufficiently expressive, 

 later observers have founded several subdivisions, partly derived from 

 mere external aspect, partly from organic structure. Pei'haps their ar- 

 rangements are susceptible of smiplification, therefore of improvement ; 

 for too little notice has been ^axiA to vigorous living specimens kept 

 for permanent study, that they might be rendered authority. 



To the superficial observer, a common resemblance pervades this 

 numerous tribe ; in several arms radiating from a central disc, in crawl- 

 ing backward and forward, from side to side, or around in all directions 

 indifferently, and in adhering to the substances whereon they rest. 



All inhabit the sea ; nor does any animal bearing the slightest re- 

 semblance to the Star-fish, dwell in the fresh-waters distributed through- 

 out the globe. 



On closer inspection of the specimens of the tribe when brought 

 nnder view, so much diiference, so great a variety in their organization, 

 together with certain peculiarities in habits, may be discovered, as to 

 sanction their subdivision for the facility of giving intelligible descrip- 

 tion, and for recognition. 



They present a smooth and uniform surface, or they are penetrated 



