Species of British Echinodermata. 99 



anatomy, physiology, and reproduction of the Echinodermata, 

 which is beyond the scope of the present paper, but not a itw 

 memoirs have appeared on the Continent which have thrown 

 additional light on the general organization and arrangement of 

 these animals; and the writings of Agassiz, Sars, Liitken, Von 

 Diiben, Koren, J. Miiller, Troschel, Gray, Forbes (subsequent 

 papers), Grube, Dujardin, and Hupe, &c., bear testimony to the 

 great need there is of a complete revision of the nomenclature 

 and classification of the Echinodermata which inhabit the British 

 seas. Such a revision is the more required because at the tim^ 

 when Professor Forbes wrote his monograph the laws of zoo- 

 logical nomenclatui:e were not so fully recognized as they are at 

 the present day, and thus a later name was frequently applied 

 to a species while the author was fully conscious that the animal 

 had been described under another name at an earlier date. 



For some time past we have been urged by friends interested 

 in the study of the Echinodermata to prepare such a revision, 

 the want of which has been very generally felt. In the follow- 

 ing paper we will attempt to do so. The object which we shall 

 have in view is fourfold : 1st, to revise the nomenclature of the 

 species described in the ' History of British Starfishes,' and rcr 

 distribute them in the genera now generally recognized ; 2ndly, 

 to give the characters of all the orders, families, and genera; 

 3rdly, to describe all those species which have been discovered 

 in our seas since the publication of Forbes's work, or which 

 require to be redescribed in order that they may be more readily 

 distinguished from certain allied forms now incorporated in our 

 lists ; 4thly, to give some information as to the geographical 

 distribution of the species. 



Among the Echinodermata which will be here introduced as 

 supplemental to those of Forbes's work are many which have 

 not hitherto been published as British, though some of them 

 have been mentioned as additions to our fauna, and exhibited 

 by the author at recent meetings of the British Association. 



We have adopted a plan with respect to the synonymy which 

 will at once show the reader why we have employed the name 

 which is here given to the species. The dates prefixed to the 

 references, and the brief notes here and there appended to them, 

 will in most cases, without any paragraph -observations, suffice 

 to render obvious the causes of any change in nomenclature 

 which may have been made. We have given as few references 

 as are consistent with the end to be attained. To writers of 

 earlier date than Forbes we have only referred when it was ne- 

 cessary to establish the date of a name. The synonymy quoted 

 from more recent writers is intended to show what authors first 

 introduced any particular change of name, or, in some cases, 



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