CEPHALOPODA. 



SINCE the publication of the first part of this work, the Red Crag "diggings" have turned up portions 

 and segments of Nautilus and Ammonites, but these, like the Belemnites, are derivative fossils, and may be 

 traced to antecedent Formations ; the Nautilus apparently to the London Clay, and the Ammonites to one 

 of the middle Secondary Periods.* The Cephalopods living in our own seas, and even in those of more 

 southern latitudes, like the Mediterranean, in association with a Marine Fauna similar to that of the 

 Coralline Crag, are of such a perishable nature, and possess so little of preservable material, that, except 

 under very favorable protection, should we be likely to find any portion of their remains. What are called 

 the Tetrabranchiata, with strong calcareous shells, such as those from the Middle Tertiaries of Bordeaux 

 and Dax, do not appear to have extended their existence into the sea of the Coralline Crag, although the 

 Pynda and Pholadomya (tropical forms), when first obtained in the Deposit of that Period, gave a slight 

 hope that the Nautilus might also there be met with.f 



" In my cabinet are casts also of several species of Univalves and Bivalves, which, so far as such 

 fossils will permit of an identification, are of shells belonging to the Older Tertiaries ; and I will here men- 

 tion that, although a few of the extraneous organic remains of the Red Crag may be traced to the Chalk 

 and Older Secondaries, the great majority I believe to have been derived from the Eocene Deposits, and 

 principally from the London Clay proper, along with the phosphatic nodules ; and I would assign to the 

 same source (the Older Tertiaries) the marine Vertebrata, Carcharodon, Lamna, Myliobates, Pycnodus, 

 Phyllodus, Edaphodon Pristis, &c. &c., as well as the Cetacea, recently found in such abundance, and the 

 Crustacea (Zanthopsis, &c.), the abrasion, by coast action, being, in my opinion, sufficient to produce all 

 the effects now visible in the Red Crag, with the sea of that period opening to the northward. Christchurch 

 Bay, between Handfast Point and the Needles, may perhaps furnish us with a parallel. 



f In the second part of the ' Eocene Mollusca,' by F. E. Edwards, Esq., is an address to the subscribers 

 of the Palseontographical Society, respecting the Siphuncular Theory of the Cephalopoda. The author, 

 when treating of the tube which perforates the chambers of the shells in that class of animals, attributed to 

 myself the priority of pointing out a new explanation of the function of that organ, one which seems now 

 to be generally admitted, and published in his own and better language the statement I had given him of 

 my opinion, and the arguments used in support of it. This priority has, it seems, been laid claim to in 

 the sentence quoted in that address. I have, until now, remained silent upon the subject, and would 

 gladly have continued to do so, had not some of my friends expressed a desire that I should defend myself 

 from what, to them, appears to be capable of being interpreted into an appropriation of the discovery of 

 another as my own idea. The only defence that can now be offered is, that I was wholly unconscious of 

 any other function than that of a hydrostatic balance having ever been attributed to this tube, and I con- 

 fess to my having been unacquainted with the paragraph referred to. 



The necessity of maintaining an integrity of character, and the preservation or permanence of adhesion 

 in the inorganic elements in these Cephalopods, occurred to me from the especial study of Bulimus decol- 



