about actively by means of cilia. During
their larve life, the sea-acorns search for
habitats fulfilling the conditions needful for
them, and find them on rocks, stones, piers,
breakwaters, timber, ships, boats, turtle,
about the eyes of the whales, or under the
umbrella of the medusæ. The folds of their
mantle seem to serve them as gills. We owe
valuable glimpses of the structure of these
creatures to the labours of Dr. Martin, Saint
Ange, and Mr. Charles Darwin. Deep
darkness appears, however, still to cover the
mysteries of their reproduction.

The large balani are capital eating.
Athenæus and Macrobius say, the Egyptian
sea-acorns were esteemed good eating by the
ancients. Macrobius says, white and black
balani were served up at the banquet given
by Lentulus when he was received among
the priests of Mars. Captain King tells us,
acorn-shells, or sessile balani, are found at
Concepcion de Chili, and sold at Valparaiso,
which are three inches broad and five and
a-half long. After being boiled, they are
eaten cold, and deemed a great delicacy, their
flesh equalling the richness of the crab.

General exposure in the air, with
occasional wettings and dippings in sea water,
are the conditions of life preferred by the
balani colonies. Unless the epidermes of the
whales form an exception, they do not
penetrate into the substances to which they
attach themselves. Social and sympathetic
creatures, their bases press close together in
a way which frequently disturbs the
symmetrical regularity of their forms. The
balani are the animals, as the ulva are the
plants of the zone of spray.

The brown zone commences where the
green zone ends, below the high-water mark
of ordinary tides. This band of coast is the
bed of the sea-girdles and the sea-wands, and
might be described as the pasture-fields of
the limpets and the periwinkles, who browse
upon them.

Limpet, the Saxon name, is derived from
"impan," to plant or to graft into; or from
"limpian," to adhere or belong to as a limb.
The limpet is the graft or limb of the rock.
Patella, the learned name, is the Latin word
for a tartlet. The Greek or Latin observer
was struck with the form, which resembles a
pasty; the Saxon with the practical quality,
the adhesiveness of the sea-side animal. The
laminarian zone is the habitat of the limpets
and periwinkles, because as herbivore they
feed upon the plants composing it. When
the sea is smooth and the tide up, they crawl
about upon the sweet tangles and esculent
badderlocks. The tongue of the limpet is a
ribbon, two or three inches long and half a
line broad, crossed by rows of hooked teeth
four deep, with a pair of three-pronged
sawlike teeth between every row. The action of
this instrument upon the fronds of the
laminaria is one of the most curious performances
in the ocean theatres.

When the tangles which have been washed
on shore are taken up and examined, they
are generally found to have been eaten at the
roots and fronds. The limpet which eats the
fronds is called the patella pellucida, and the
one which eats the roots is the patella lavis.
Indeed, a heap of sea-wands is a treasure
trove. The pellucid limpet is found on the
frond, and the cerulean limpet is ensconced
in a cave in the very centre of the bulbous
root.

The limpet is conic-shaped, with a circular
and somewhat oblong base. The distinct head
has a thick and short trump; two pointed
feelers carry eyes at their base, and the long
tongue folds itself up backwards into the
stomach. M. Milne Edwards has made a
singular observation respecting the patella.
He found a part of the buccal apparatus
enclosed in the aort or great artery of the
heart. The locomotive, a muscular disk
under the body, is large and round, but
overhung by the edges of the mantle. Some
naturalists call the limpets the circle gills
(cyclo-branches), because their gills are a
circle of leaflets running round between the
mantle and the locomotive. I have never seen
any trace of a glue upon the locomotive of
the limpet. The muscular disk adheres just
as the boy's leather sucker does, by the
exclusion of air. There is in the disk not
merely a power of adhesion to the exclusion
of air, there is a suction of the substance of
the rock. I have dislodged a limpet from a
sunk locality, almost the tenth of an inch
deep, which was the exact shape of the disk,
and must have been produced by its
corroding suction. The circle of breathing
leaflets is above the disk, and between it and
the mantle. When a limpet is touched, the
shell descends and presses against the rock.
Adhering by the suction of a muscular disk,
and breathing by means of gills encircling it,
the limpet defies all the ordinary dashings of
the breakers, and breathes securely when
seemingly glued into the rocks as limbs.
Feeding upon tangles and reposing upon
rocks, a shell was necessary for the limpet,
from which the breakers would glide off
dispersedly. The shell accordingly resembles
an ancient buckler, formed to turn aside the
points of spears. The conical forms, indeed,
of the balani and the limpets are adapted to
confront the breakers. The sea acorns, as
they cannot change place, establish
themselves where only the edges of the farthest
reaching waves can break upon them. When
the swell of the sea warns them of the
approach of a hurricane, the limpets flee to
the rocks. Observers in the Orkneys have
seen limpets which had climbed seventy
feet up the face of the rocks to escape the
Niagara floods which the stormy Atlantic
discharges against the shores. However
well they may be formed to resist the shocks
of the ocean, they wisely deem it prudent
to get out of the way of waves which toss