Page 288 - (DK) Ocean - The Definitive Visual Guide

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CLASS GASTROPODA CLASS GASTROPODA
Three-tooth Cavoline Sea Hare

Cavolinia tridentata Aplysia punctata
LENGTH LENGTH
1 / 2 in (1 cm)
Up to 8 in (20 cm)
HABITAT HABITAT
330–6,500 ft Shallow water
(100–2,000 m); carried
in ocean currents
DISTRIBUTION Warm oceanic waters worldwide DISTRIBUTION Northeast Atlantic and parts of the
Mediterranean
This species of sea butterfly has a
small, almost transparent, spherical The sea hare, a type of sea slug, has
shell with three distinctive, posterior tentacles reminiscent of a hare’s ears.
1
projections. The shell also has two slits It has an internal shell about 1/2 in
identified. Its soft body parts are through which large extensions of the (4 cm) long that is visible only
CLASS GASTROPODA
delicate and translucent with a mantle pass. These brownish “wings” through a dorsal opening in the
Bubble Shell fluorescent blue margin and, in form, are ciliated and so can create weak mantle. If disturbed, it releases purple
reminiscent of the Spanish dancer water currents as well as aid buoyancy. or white ink. It is not known if this
(opposite), which is a close relative Sea butterflies are unusual among response is a defense mechanism.
Bullina lineata
LENGTH that has lost its shell. If threatened, shelled mollusks in that they can live
1 in (2.5 cm) the bubble shell quickly withdraws in open water. Like other members
HABITAT into its shell and at the same time of this group, the three-tooth
Sand, reefs to 65 ft regurgitates food, possibly as a defense cavoline produces a mucus web
(20 m), mainly intertidal;
subtidal at range limits mechanism to distract predators. very much larger than itself,
The bubble shell is itself a voracious which traps planktonic
DISTRIBUTION Tropical and subtropical waters of predator, feeding on sedentary organisms, such as diatoms and
Indian Ocean and west Pacific polychaete worms. This mollusk the larvae of other species. It eats
is hermaphroditic and produces the web and the trapped food at
The pale spiral shell of the bubble characteristic spiral intervals, then produces a new one.
shell (also known as the red-lined white egg During their lifetime, sea butterflies
bubble shell) has a distinctive pattern masses. change first from males into
of pinkish red lines by which it can be hermaphrodites and then into females.

CLASS GASTROPODA CLASS GASTROPODA
Polybranchid Hermissenda
Sea Slug
Cyerce nigricans
LENGTH
Hermissenda crassicornis
Up to 1 / 2 in (4 cm)
1
LENGTH
HABITAT
Reefs Up to 3 in (8 cm)
HABITAT
Mud flats, rocky shores
DISTRIBUTION Western Indian Ocean, western and
central Pacific
DISTRIBUTION Northwest and northeast Pacific
This colorful sea slug is a herbivore
that browses on algae. It has no need This sea slug, usually known simply
of camouflage or a protective shell, as as Hermissenda, has an unusual way
it has two excellent alternative defense of deterring predators. It separates the
strategies. First, it can secrete distasteful stinging cells from any organism it eats
mucus, by utilizing substances in the and stores them in the orange-red tips
algae it feeds on and secreting them of petal-like tentacles, or cerata, that
from small microscopic glands over the cover its back. Any creature that
body. Second, its body is covered with touches the cerata is stung. Unlikely
petal-like outgrowths called cerata, though it seems, Hermissenda is used
spotted and striped above and spotted CLASS GASTROPODA extensively by scientists conducting
below, that can be shed if it is attacked in cracks and crevices. Since it cannot memory experiments. The animal has
by a predator, in the same way as a Chromodorid swim, it glides over the tropical reefs an excellent sense of smell that enables
lizard sheds its tail. This ability to cast on which it lives on its muscular it to find its way around mazes to
off body parts to distract predators Sea Slug foot, secreting a mucus trail much locate food, and it can be “taught”
is called autotomy. as terrestrial slugs do. The different to respond to simple stimuli.
The cerata are also used in Chromodoris lochi species of the genus Chromodoris are
respiration, their large collective surface LENGTH distinguished by the pattern of black
area allowing efficient gas exchange 1 1 / 2 in (4 cm) lines on their backs and the plain color
with the surrounding water. The head HABITAT of their gills and rhinophores (a pair
carries two pairs of sensory organs— Reefs of olfactory organs at the head end).
OCEAN LIFE (rhinophores). These are retractile and DISTRIBUTION Tropical and subtropical western and mate. To do so, they must face in
The two chromodorid sea slugs
the oral tentacles near the mouth and,
further back, the olfactory organs
pictured here are possibly about to
central Pacific
subdivide as the polybranchid matures.
opposite directions so that their sexual
openings are aligned. As they are
They are used to assist in finding food
Protected from predators by its bright
and mates. There is some debate as
hermaphrodites, they both produce
sperm, which they exchange during
warning coloration and unpleasant
to whether this sea slug is a separate
species or is simply a color variation
taste, the chromodorid sea slug forages
mating, and both later produce
fertilized eggs.
in the open, rather than hiding away
of a similar mollusk, Cyerce nigra.