GASTEROPODA. 21 



dextral individuals, and so progressed through the various subsequent formations until, 

 by the decrease of the sinistral and increase of the dextral individuals, the species has 

 attained in these seas to its present condition, wherein millions of dextral individuals 

 occur to one sinistral. The late Edward Forbes mentions the occurrence in the Irish 

 Drift of the sinistral form, and if it be the case that Nucula Cobboldia occurs in that Drift 

 in association with it, as has been said, that occurrence would be in accordance with the 

 antiquity of both these shells in the seas of Britain. 



Trophon Berniciensis ? King. Supplement, Tab. I, fig. 8, a, b. 



Fusus Berniciensis, King. Ann. and Mag. Nat. Hist., vol. xviii, p. 246. 



Locality. Eluvio-marine Crag, near Norwich. 



The above (fig. b) represents a specimen which was sent to me by the late Dr. S. P. Wood- 

 ward for examination ; it was accompanied by the following note : — " I have compared my 

 new Fusus from the Norwich Crag with the figure of T. Spitzbergensis, and find them agree 

 very well in the character of the spiral striae ; but the recent shell has a more contracted 

 canal/' The very young condition of the " Norwich Crag " shell is much like Spitz- 

 bergensis, but the resemblance is less so when it is full grown. I think it more resembles 

 the British shell T. Berniciensis, King, although with this it has not a perfect identity. 

 Another specimen (fig. 8 a) has been more recently obtained from the same neighbour- 

 hood which appears to belong to the same species. This was found by Mr. John King, 

 of St. Andrew's, Norwich, who has obligingly permitted me to have it figured. I have 

 given to it provisionally the above name with a doubt, but if from future discoveries it 

 should prove to be a new species I Avould suggest that it be called T. Woodicardii. 



Trophon Norvegicus, Chemn. Supplement, Tab. V, fig. 14. 



In the ' Crag Moll.,' vol. ii, Tab. XXXI, fig. 1, is represented a specimen of what I 

 then believed to be the species here referred to, and I have now another very nearly 

 perfect from the cabinet of Mr. Canham, who has obligingly permitted me the use of 

 it. It came from the nodule pits of the Red Crag at Waldringfield. This shows a more 

 elongated form than the living shell, with a comparatively smaller aperture and more 

 recurved canal. The outer lip is not quite perfect, but if it were, it would rather help 

 to diminish the smaller proportions of the aperture. 



