206 Frocecdings of the Royal Physical Society. 



cation the material gathered for use in my own investigations. 

 I should, however, be doing injustice to Mr Tryon did I not 

 acknowledge my indebtedness to his elaborate and careful 

 index. 



At present no systematic treatment of the whole class of 

 Cephalopoda can hope to be other than provisional. Such 

 a large percentage of the published descriptions of species 

 are inaccurate or insufficient for modern requirements, that 

 nothing satisfactory can be obtained until some worker shall 

 travel to the various museums and re-examine all such type 

 specimens as are at present extant ; and it would be par- 

 ticularly desirable that he should have the opportunity of 

 comparing the different specimens side by side. 



With respect to the list itself, I have endeavoured to give 

 a reference to the original creation of each species and such 

 others as might be necessary to indicate the important points 

 in its history, or good descriptions and figures of it ; save in 

 one or two cases of special interest, I have not attempted to 

 give complete synonymies. I have especially avoided regis- 

 tering species as identical without such evidence as seemed 

 to me conclusive, for, so far from tending to simplicity and 

 clearness, hasty and indiscriminate identifying of species can 

 only lead to the utmost confusion. It is, too much to hope 

 that there should be no mistakes in the references, but 

 every care has been taken to reduce them to a minimum ; 

 with the exception of a few, where the contrary is distinctly 

 stated, they have all been personally verified by myself. 



The Classification adopted is not identical with any pre- 

 viously published, but I have endeavoured to select what 

 was best from the works of my predecessors, modifying their 

 results when it seemed necessary. A systematic arrange- 

 ment of this class, based on a complete knowledge of their 

 anatomy and development, as well as of their external 

 characters, is still and will long remain a desideratum. 



The present list contains 388 species, which are disposed 

 in 68 genera, and these in 14 families. Of these at least 60 

 or 70 species have been inadequately characterised, so that 

 it is unlikely that they could be recognised from the pub- 

 lished descriptions, and the same is true of several of the 



