On some new British species of Nudibranchiate Mollusca. 189 
above-mentioned orifice at the apex of the leaf, from whence it is 
thrown forth by pulsation. At each pulsation a small globule 
of clear tasteless water was ejected. Each drop, as it fell from 
the leaf, contained fifteen of these globules, and eleven drops fell 
in the course of a minute. This action begins with the shades 
of the evening and continues until the heat of the sun changes 
the course of action. Each full-grown healthy leaf will produce 
about half a pint of water during the night, which on being ana- 
lysed has been found to contain a very minute portion of vege- 
table matter. The veins which flow into this duct may be di- 
stinctly traced by the light of a candle (the leaf being held be- 
tween) from the body of the leaf to the midrib, and from thence 
followed down perhaps the one-half of the foot-stalk, where, from 
the colouring matter of the leaf becoming denser, they are ulti- 
mately lost sight of. There is also a smaller duct which runs 
parallel to the larger and nearly close to it, the use of which is 
not so clearly marked, but from observation it appears to be con- 
nected with another series of vessels running from it towards the 
interior, but terminating before they reach the midrib. 
From the time the plant began to grow rapidly in April, its 
treatment was after the following manner : — Some turf, that had 
been cut from an old pasture a few months before, being chopt 
into pieces in the form of brickbats, all the loose small earth 
being taken away, a small portion of rough charcoal and half-de- 
cayed dry manure was added, which, being chiefly fibrous, allowed 
water to be given copiously, and admitted the roots freely to feed 
on the vegetable matter. There are but few kinds of plants that 
will not thrive in a most luxuriant manner treated in this way. 
As a finish in potting, a small portion of a fine mixture of soil on 
the surface gives neatness, as well as prevents too great an action 
of drought in drying weather. 
I am. Sir, yours most obediently, 
J. Yates, Esq, Francis Williamson. 
XX . — Additions to the British species of Nudibranchiate Mol- 
lusca, By Joshua Alder and Albany Hancock*. 
Some new forms of Nudibranchiate Mollusca have occurred to 
us during the last and part of the preceding years, of which we 
now purpose giving an account. 
And first we would notice the interesting addition made to our 
fauna by the discovery of Scyllaa pelagica on the British shores. 
This well-known inhabitant of the deep was found by Mr. W. P. 
* Partly extracted from a paper read at the British Association Meeting 
at Oxford. 
