A Revised List of Brilisk Ecliiuoidea.' 399 



"Revised List of British Opliiuroidea; " and Mr A. Somer- 

 ville, F.L.S., the energetic secretary of the Glasgow Natural 

 History Society, suggested that I should continue the work 

 which I then commenced, and kindly offered to communicate 

 the paper to his society. 



I felt, however, that as the Eoyal Physical Society had 

 done me the honour of publishing my first work in this 

 direction, any further papers I might be able to write upon 

 the same subject ought in the first instance to be offered to 

 it. At the time when Mr Somerville made his sujrcrestion, 

 I had just completed a series of dredgings in the Clyde sea 

 area, and had thus collected a considerable number of some 

 of our common forms ; and, furthermore, I was spending some 

 months in London, and was thus enabled to enjoy the 

 inestimable privilege of being able to consult the collections 

 and libraries of the British Museum ; whilst, to crown all, my 

 friend Dr Norman generously gave me access to the materials 

 which he had been amassing for his own projected work upon 

 the group. 



In drawing up the present list I have naturally taken 

 Forbes's handbook as a starting-point, and have endeavoured 

 to add to it all those species which have since been recorded 

 as British, and to bring the nomenclature into harmony with 

 the principles now generally adopted. For this latter work 

 the " Revision of the Echini," by Alexander Agassiz, is now 

 the standard. He has treated the synonymy so exhaustively 

 that to give it over again would simply be to reprint selec- 

 tions from his work, and would add nothing to the practical 

 utility of such a catalogue as the present. I have therefore 

 contented myself with a reference to the original creation of 

 each species, and to such other authorities as are of essential 

 service in its identification. 



The attempt has also been made to give a brief diagnosis 

 of each species, such as will enable the collector to identify it 

 on the spot ; but these notes will not stand in the place of 

 more complete descriptions, still less can they be appealed to 

 as decisive in critical cases, when one of the first authorities 

 upon the group writes as follows : — " It seems almost hope- 

 less to attempt to distinguish the species of Ecliimis known 



