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Proceedings of the Royal Physical Society. 



XXIY. A Catalogue of Recent Cephalopoda.. Second Supple- 

 ment, 1897-1906. By William E. Hoyle, M.A., D.Sc, 

 Director of the Manchester Museum. 



(Received 5th Febmary 1909 ; read 22nd February 1909.) 



In the year 1886, the Royal Physical Society published 

 a " Catalogue of Eecent Cephalopoda," and in 1897, a Supple- 

 ment giving the names of new species published during the 

 decennium 1887-1896. I now venture to lay before it a 

 second Supplement, dealing with the additions made to our 

 knowledge during 1897-1906. So much valuable work 

 has been published during this period, that I have found it 

 advisable to modify the classification then adopted.^ 



The number of new specific names amounts to 69, and 

 of new genera to 29. There has been manifest a distinct 

 tendency to the subdivision of genera, with the result that 

 many of these now only contain one species each. It appears 

 to me that this is a procedure to be deprecated, as tending 

 to conceal the affinities of different forms, and increasing the 

 difficulties of systematic and distributional work. At the 

 same time, it seems an almost inevitable result of speciaKsa- 

 tion in zoological studies. The student who confines his 

 attention mainly to one group of animals, becomes more and 

 more impressed with their divergences. He recognises large 

 numbers of local races, which his predecessors did not 

 differentiate, and finds it convenient to distinguish these by 

 names, which soon come to be regarded as specific, and 

 almost of necessity the species come to be grouped in more 

 numerous divisions, which naturally receive generic names. 

 Thus we find that of the 29 new generic names above-men- 

 tioned, 10 have not been created for the reception of newly- 

 discovered forms, but by dividing or renaming older genera. 



Among the most important publications of the decade 

 must unquestionably be reckoned the Symp)sis der oegopside/i 

 Cep)halopoden of Dr Pfeffer, which fitly appeared just at the 

 close of the nineteenth century, and very adequately repre- 

 sented the state of our knowledge of this group at that 



^ Largely because the structure of the heetocotylised arm does not seem to 

 possess the high systematic value attributed to it by Steenstrup ; see Appellof, 

 '98; Hoyle, :o8. 



