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 Cobboldie 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 Brrnictensis? King. Supplement, Tab. I, fig. 8, a, 4. 
Fusus Bernicrensis, King. Ann. and Mag. Nat. Hist., vol. xviii, p. 246. 
Locality. Fluvio-marine Crag, near Norwich. 
The above (fig.4) represents a specimen which was sent to me bythe 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 7. Sp7tzbergensis, and find them agree 
very well in the character of the spiral strize ; but the recent shell has a more contracted 
canal.’ The very young condition of the “Norwich Crag” shell is much like Spzz- 
bergensis, but the resemblance is less so when it is full grown. I think it more resembles 
the British shell 7 Beruiciensis, 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 would suggest that it be called 7. Woodwardi. 
TrorHon Norvucicus, 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. 
