2 THE VOYAGE OF H.M.S. CHALLENGER. 



special interest, I have not attempted to give complete synonymies. I have especially 

 avoided registering species as identical without such evidence as seemed to me absolutely 

 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 previously published, but I have 

 endeavoured to select what was best from the works of my predecessors, modifying their 

 results when it seemed necessary. A sj^stematic arrangement 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 which numbers 32 species, 4 genera, and 1 family are new to 

 science. Of these at least 60 or 70 species have been inadequately characterised, 

 so that it is unlikely that they could be recognised from the published descriptions, and 

 the same is true of several of the genera ; hence it may be said in round numbers that 

 we are acquainted with 50 genera of recent Cephalopoda containing 300 species. It is 

 worthy of remark that 29 or half the genera contain only one species each, while 

 nearly one-half the species (170) belong to the three genera Octo'pus, Sepia, and Loligo. 



