Phylum Cnidaria (Coelenterates) Jellies Anemones Corals Hydroids.

Phylum Cnidaria (Coelenterates)

• Jellies• Anemones• Corals• Hydroids

Hydroids (2) & Hydrocorals (2)

Hydroids- usually colonial, skeleton looks branchy like a fern, individual

polyps are attached to branches. Complex life cycle.

Hydrocorals- colonial, marine hydrozoans with a limestone skeleton.

(resemble true corals).

Christmas Tree

• Hydroid

Portuguese Man-Of-War• Hydroid• Dangerous nematocysts-don’t touch and don’t try to pull one off of your friend (you’ll get stung too!)

Branching (Encrusting)Fire Coral

• Hydrocoral• Don’t touch…these

are one reason to be thankful you’ll be wearing a wetsuit!

Blade (Leafy) Fire Coral

• Hydrocoral

Jellyfish (2)

True Jellyfishes- translucent, unattached medusae, swim in open

water, consist of prominent dome and nemotocyst-bearing tentacles

Sea Thimble

• Jellyfish• Tiny and numerous!• We may see these in Andros, but they only sting your

mucus membranes, so you can touch them with your hands!

Upside-down (Cassiopea)• Jellyfish• Blend in well, look in warm shallows• May be coin to pancake size

Gorgonians (8)

Gorgonians- commonly called “soft corals”, lack rigid, permanent

skeletons. Central core is surrounded by gelatinous “rind” with imbedded

polyps.

Corky Sea Fingers

• Gorgonian

Black Sea Rods

• Gorgonian

Porous Sea Rods• Gorgonian• Picture showing pore-like polyps

on right

Bipinnate Sea Plume

• Gorgonian

Yellow Sea Whip

• Gorgonian

Angular Sea Whip• Gorgonian• Commonly seen on

our snorkels. • Picture below shows

details of polyps.

Common Sea Fan

• Gorgonian• Ones we see

will have purple

colored “veins”.

Venus Sea Fan

• Gorgonian• Notice yellow colored

“veins” on the sea fans on the left.

Anemones (4)

Anemones- solitary polyps attached to bottom of sea, lack hard skeletal

parts. Tentacles with nematocysts sting and capture prey which is then

inserted into mouth on oral disc. May contract tentacles for protection.

Giant (aka: Pink-Tipped)

• You will probably see these, especially during our invertebrate walk. Usually pretty small (1-3 in)

Sun

• Anemone

Elegant (Burrowing)

• Anemone

Corkscrew

• Anemone• Look for these

attached to patch reef or wreckage

Zoanthids (2)

Zoanthids- similar to anemones, but tiny (<1/2 in.) and mostly colonial.

Only has 2 rings of tentacles.

Mat

• Zoanthids

White Encrusting

• Zoanthid

Corals (13)Stony Corals- hard corals, reef builders.

Polyps secreting calcium carbonate to form hard cups (corallites) that protect soft bodies.

Increase in size by asexual budding.

NOTE: When snorkeling over a coral head, look for combinations of stony coral,

gorgonians, anemones and other organisms all living together.

Staghorn • Coral• You will see these

often on the main reef!

Elkhorn

• Coral• Ginormous!• These have made a comebackaround Andros~you should see lots!

Finger (Clubbed-finger)

• Coral• Commonly seen on our trip.• Look for the large wall of finger coral by the

oceanic blue hole

Pillar

• Coral

Great Star

• Coral• Smaller picture shows individual polyps

Boulder Star

• Coral

Elliptical Star

• Coral

Golfball

• Coral

Mustard Hill

• Coral• You should see these

nearly every day.

Symmetrical (Smooth) Brain

• Coral

Grooved Brain

• Coral

Rose• Coral• Elliptical on left• Hemispherical on right

Lettuce

• Coral

The End

Study your field guides and feel free to access this PowerPoint for review

purposes on the Marine Biology website!