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some scores of specimens of this shell in the young state with 
the spiral nucleus attached, besides great numbers of separate 
spirals ; the intermediate length of tube between the young 
and the adult state increases rapidly in size, and has a decidedly 
conical shape, so that the whole length of the shell, if it were 
to remain entire, would not be so great as might be supposed 
from seeing only the young and the mature portions. Skenea 
rota occurs sparingly ; I have seen about half-a-dozen speci- 
mens. The minute shells which have proved perhaps the most 
interesting are those of the fry of different species of limpet, 
four forms of which have been met with ; they are exceedingly 
abundant in the shell sand, and three of the species have a 
distinct spiral cap surmounting the apex of the conical part. 
The series of mounted specimens shows very clearly the 
several stages of growth to the adult form, and it will be seen 
that an internal partition is formed by degrees until at last it 
completely divides the interior of the cone from that the larval 
cap, which then drops off, leaving a depressed oval scar near 
the apex. Patella pellucida is at once distinguished by its 
brilliant greenish-blue marks; it is smooth and has a semi- 
transparent horn colour, much like that of the adult, though 
it gives little promise of the elegant shape it afterwards grows 
to ; the larval cap is large and its spiral character distinct. 
A second form has so much the appearance of Patella vulgata 
that I shall venture to call it so. The cap is smaller than in 
P. pellucida, and the conical shell is opaque and strong, and 
has radiating ribs and markings of colour resembling the adult 
P. vulgata ; in this shell the scar left when the cap has fallen 
is much deeper and coarser than in P. pellucida. A third 
form, which is much the most abundant in the sand, has a 
smooth, delicate, colourless shell, sometimes quite transparent, 
but often partly or wholly opaque ; the cap is always white 
and has the appearance of a drop of wax on the apex of the 
cone. In this species the conical shell from its first com- 
