NOTE ON SOME POST-PLIOCENE MOLLUSCS FROM THE BYCULLA FLATS. 191 



of analogy of Teredo and Dentalium make it appear that the former is 

 the passage between Lamellibranches and Gasteropods ; that is to say, 

 putting the proposition in a more popular form, Kuphus may be 

 regarded as the connecting link between bivalves and univalves. Lastly, 

 in May 1875 was published an illustrated paper on Kuphus in Reeves' 

 "Conchologia Iconica" (probably written by Mr. Sowerby, Mr. Reeves 

 having died in 1865), which thus describes the genus Kuphus, Guttearcl 

 Cyphus : — " Mollusc ; sand-burrowing ; tube large, white, rough, 

 slightly ringed ; posteriorly attenuated ; divided interiorly into two 

 tubes ; chambered transversely with septiform laminae ; valves un- 

 known; compressor palmets shelly deltoid." 



The writer goes on to point out that the general appearance of the 

 tube is so like that of the Teredo as to leave little doubt of the nature 

 of the animal and its affinity with the genus Teredo. At the same 

 time he says it can hardly be included in that genus, the valves having 

 never been seen, and it being certain that the animal does not bore like 

 the Teredines. 



He figures two species, giganlm and clausa, the former of which 

 has the lower end broadly open, the latter closed in a rounded oval 

 disc with a visible suture. 



It is hard to see how, with a closed and rounded end, inside which 

 the valves, if any, must be situated, the animal can have conducted 

 its boring operations through the mud, especially as the shell at this 

 part is described as very thin. I have a theory, of course a mere guess, 

 as I have never seen the anterior extremity of the shell, which you 

 may think it presumptuous in me to advance, but still it does seem to 

 me not impossible that the closed end may be not the characteristic of 

 a species, but due to the act of the individual. We have noticed the 

 rounded projections, the shell of which is very thin, occurring wher- 

 ever the animal stopped progressing in the old direction and started 

 in a new. Suppose for any reason he did not start again, the tube 

 would end in a rounded projection. Might not this account for the 

 rounded ends of some specimens ? Sir Everard Home, in his paper 

 already mentioned, says that both Teredo gigantea and Teredo 

 navalisj when arrived at their full growth, close up the ends of 

 their shells, and that death is not the consequence of this act. In 

 some of Mr. Griffiths' specimens he says the shell was considerably 

 thickened at the end, and in a few the animal had receded up the 

 tube, forming new inclosures more than once, and at the same time 

 thickening the walls of the tube so as to diminish the canal in 



