Hydra (whole mount) Cl. Hydrozoa,
A-tentacle, B-hypostome, C-body column,
D-basal disc
Hydra (longitudinal
section; 234K) Cl.
Hydrozoa
A-mouth, Bhypostome, Cgastrovascular cavity,
D-epidermis, Emesoglea, Fgastrodermis
Hydra (cross section; 259K) Cl. Hydrozoa
A-epidermis, B-mesoglea, C-gastrodermis, Dgastrovascular cavity
Hydra (cross section, higher power; 256K) Cl. Hydrozoa
A-mesoglea, B-gastrodermis, C-epidermis, D-nematocysts in cnidocytes; outer body
surface is to upper left
Hydra
Locate: gastrovascular cavity,
gastrodermis, epidermis, mesoglea
cs
ls
Hydra
Locate: epitheliomuscular,
gastrovascular cavity, gastrodermis,
cnidocytes, mesogloea
cs
ls
Hydra
cs
ls
Hydra
ls
Hydra
Hydra
cs
Hydra with developing ovaries
Hydra with ovaries
and buds
Single ovary,
which is a swelling
in the epidermis
occupied by a
large oocyte filled
with dark yolk
granules
Testis (three in total
were visible in this
cross-section of the
column) filled with
hundreds of tiny sperm
cells
Hydra with developing testes
(spermaries)
Sexual
egg
Young
polyp
female
sperm
male
Budding
Hydra
Asexual
Hydra Nerve
Net
neuri
neuro
te
n
Annulus
(branched upright stem)
Feeding polyp
Reproductive polyp
medus
ae
Pennaria
Aurelia
Commercially prepared slide of a planula larva. The
planula is an ovoid gastrula with a blastopore at one
end. You should be able to distinguish between the
outer ciliated ectoderm and the inner endoderm.
Rhopalium of Aurelia
Rhopalium
Rhopalium of Aurelia
Rhopalium
Rhopalium
Cassiopeia - Upside Down
Jellyfish
• Note purple vesicular
appendages
– flattened, elongate,
club-shaped
– May be distally
birfurcated
– Many sizes
– Open into the brachial
canals
• Number, size, and color
vary with sex and age
• Function is not well
understood.
Aboral surface is concave and resembles a large
sucker. This suction assists the animal in maintaining
contact with the substratum. With it the jellyfish can
remain in place on smooth vertical surfaces as you
have observed in the aquarium.
Metridium
Metridium
Oral surface of the sea anemone
showing the tentacles, mouth and
siphonoglyphs.
Cross section through a Metridium
looking towards the oral opening shows complete and incomplete
septa.
Detail of the oral opening of the sea
anemone showing the position of the
siphonoglyphs.
Internal anatomy of the sea anemone
- showing the body wall
Cross section through the middle of a
sea anemone- Shows complete and
incomplete septa.
Cross section through a Metridium
looking towards the basal disc - shows
complete and incomplete septa.
Longitudinal section of a sea anemone
showing the internal anatomy
Internal anatomy of the sea anemone showing the pharynx and the acontia
attached to the base of the cavity
Internal anatomy of the sea anemone
showing the acontia
Mesoglea
siphonoglyphs
Metridium- Cross section of the anemone,
slide, showing the body wall incomplete
septa and trilobed ends.