SOME NEW AND RARE CEPHALOPODA. 123 



bodies', their bright colours, and their relative position to the generative apparatus, we 

 may perceive an evident analogy between them, and the corpora succenturiata, or supra- 

 renal bodies of the vertebrate animals. 



The preceding dissections, combined with those which I have made from time to time 

 on other Cephalopods, belonging to the genera Sepiola, Rossia, Loligo, Onychoteuthis, 

 Sepia, Octopus, Eledone, Argonauta, and Nautilus, have, in connection with physiolo- 

 gical views, suggested ideas of the natural affinities and formation of the different groups 

 of Cephalopods, which differ in some respects from those expressed in the previous clas- 

 sifications of these highly organized invertebrate animals ; and I am induced to offer 

 them to the consideration of zoologists, as they appear to me to be more in accordance 

 with the best principles now recognised in the subdivision of other molluscous classes. 



The systems of classification of the Cephalopods existing in the best works of the pre- 

 sent day differ from each other in some material points. In one, e. g., no characters 

 of ordinal importance are recognised ; but the class is immediately subdivided into se- 

 veral minor groups, of the value of tribes or families : in other classifications, where a 

 primary division of the class into two or three orders is adopted, the characters are de- 

 rived sometimes from modifications of the locomotive organs, but more frequently from 

 different conditions of the shell : and one can scarcely suppress a feeling of surprise 

 that the modifications of the tegumentary system, the low relations of which are so 

 generally recognized in the subdivision of other classes of Mollusca, should be adopted 

 for the classification of the Cephalopods by so many systematic writers of authority on 

 Malacology. 



Lamarck {Philosophic Zoologique, 1809,) divides the Cephalopods into three orders; 

 first, into those which have a multilocular shell ; second, those which have a unilocular 

 shell ; and third, those which are without either. 



It is obvious also that the modifications of the dermal system mainly govern the dis- 

 tributions of the Cephalopoda in both editions of the Regne Animal of Cuvier. In the 

 edition of 1817 the Naked Cephalopods or Seiches constitute the first family, to which 

 the Nautili, Belemnites, Hippurites, Ammonites, Camerines, and even the Argonauts, are 

 severally regarded as equivalent groups. In the edition of 1829 considerations of the 

 affinities indicated by internal organization prevail so far as to lead to the suppression 

 of the group of Argonauts, and its union with the Seiches. The other modifications 

 consist of the additions of families, including the later discovered chambered shells pre- 

 senting new modifications of structure, such as the Actinocamax of Miller, and the Ca- 

 marines, or microscopic chambered shells. 



In 1821 Mr. Gray' proposed a classification of the Cephalopods in which a primary 

 division into three orders was distinctly recognised, and names applied to them indi- 



' Cuvier makes no mention of tliem, and they appear by subsequent anatomists to have been confounded with 

 the nidamental glands. 



2 London Medical Repository, 1821. 



