Basal Animal Phyla

Mesenchyme

Middle layer separating body walls. Loosely organized gel layer. Common of Mesohyl and Mesoglea.

Parenchyme

Mesodermal in origin. Loosely organized. Present in Triploblastic Acoelomates.

Porifera

Skeleton is composed of calcerous or siliceous spicules and/or collagenous protein.

Pinacoderm

Porifera | Outer body wall of a sponge that forms supportive matrix.

Pinacocytes

Porifera | Thin, flat, tightly connected cells that form pinacoderm.

Mesohyl

Porifera | Underlays Pinacoderm. Forms the supportive matrix for nearly all sponges.

Ostia

Porifera | Openings that function as inlets for water into the sponge body.

Choanoderm

Porifera | Inner ephitlial layer. Rests on the interior surface of the mesohyl

Choanocytes

Porifera | Flagellated cells that have a collar-like ring of microvilli surrounding a flagellum. Manages the water through currents.

Oscula

Porifera | External openings. Water exits through here.

Archeocytes

Porifera | Ameboid stem cells found in the mesohyl that can differentiate into any other cell. Accepts food vacuoles from choanocytes and distribute food throughout the sponge body

Myocytes

Porifera | Contractile cells that contribute to body movements.

Spicules

Porifera | Needlelike spikes formed by ameboid cells and are made of calcium carbonate or silica.

Spongin

Porifera | Fibrous protein made of collagen. Skeleton may be made of this.

Ascon

Porifera | Simplest and least common sponge form. Vaselike, water leads directly into Spongocoel. Osculum is a single large opening at the top of sponge.

Spongocoel

Porifera | Chamber within sponge.

Sycon

Porifera | Sponge wall appears folded. Water enters and passes through incurrent canals, then radial canals, then spongocoel. Choanocytes line the radial canals.

Leucon

Porifera | Extensively branched canal system. Water moves through branched incurrent canals leading into choanocyte lined chambers. Exits through excurrent canals. No spongocoel.

Gemmules

Porifera | resistant capsules formed from asexual reproduction. Contains masses of amoeboid archeocytes.

Cnidocytes

Cnidaria | Epidermal and/or gastrodermal cells that house cnidae.

Cnidae

Cnidaria | Used for attachment, defense, and feeding. Fluid filled intracellular capsule enclosing a coiled hollow tube. Usually has cnidocil.

Cnidocil

Cnidaria | Sits outside of cnidocyte. Triggers the operculum open and discharges the coiled tube inside cnidocyte.

Nematocyst

Cnidaria | A type of cnida used in food gathering and defense that may discharge a long tube with spines that penetrate the prey.

Polyp

Cnidaria | Usually asexual and sessile. Attaches to substrate at the aboral end, has a cylindrical body, and a mouth surrounded by food-gathering tentacles.

Medusa

Cnidaria | Free swimming and shaped like an inverted bowl.

Planula

Cnidaria | Free swimming larva that attaches to a substrate

Hydrozoa

Cnidaria | Distinguishing Features:

• Nematocyst are only in the epidermis.

• Gametes are epidermal and released to the outside of the body rather than into the gastrovascular cavity.

• Mesoglea is largely acellular.

Gastrozooid

Cnidaria | In Obelia, the planula develops into a feeding polyp called:

Gonozooid

Cnidaria | Reproductive polyp that produces medusae by budding.

Velum

Cnidaria | Present on most hydrozoan medusae but is absent in all other cnidarian classes.

Nerve Ring

Cnidaria | Concentration of nerve cells in Gonionemus that encircles the margin of medusa. Coordinates swimming movement.

Statocyst

Cnidaria | Sensory structures. Consists of a small sac surrounding Statolith.

Hydra

Cnidaria | Features:

• Hangs from the underside of floating plants in clean streams and ponds.

• Lacks a medusa stage.

• Reproduces both Asexually, by budding from the side of the polyp, and sexually.

Zooids

Cnidaria | Individual polyps and medusae of order Siphonophora.

Nectophore

Cnidaria | A type of Zooid that cannot feed and is dependent on feeding polyps, but performs swimming functions for the colony.

Siphonophora

Cnidaria | Order of hydrozoa. Large. Example is Portuguese man-of-war.

Staurozoa

Cnidaria | Class ___. Has characteristics of:

• Lack a medusa stage.

• All are marine.

• Body forms in the shape of a goblet with a series of eight tentacle clusters attached to the margin of a goblet.

Scyphozoa

Cnidaria | Characteristics of:

• All marine and are "true jellyfish".

• Unlike hydrozoan medusae, medusae lack a velum.

• Cnidocytes occur in the gastrodermis as well as the epidermis, and gametes are gastrodermal in origin.

• Dioecious.

Scyphistoma

Cnidaria | Scyphozoan planula develops into a polyp called ____.

Ephyrae

Cnidaria | Budding of scyphistoma produces a miniature medusae called ____.

Rhopalia

Cnidaria | Aurelia has eight specialized structures for sensing called:

Cubozoa

Cnidaria | Box jellyfish. Can probably form images and are active predators with potent venom.

Velarium

Cnidaria | Cubozoans have this. Creates an efficient jet-propulsion swimming locomotion.

Hydrostatic Skeletons

Cnidarian movement. Water or body fluids confined in a cavity of the body and against which contractile elements of the body wall act.

Anthozoa

Cnidaria | Characteristics

• Colonial or solitary.

• Lack Medusae.

• Cnidocytes lack cnidocil.

• Include anemones and soft corals.

Sea anemones

Cnidaria | Solitary, frequently large, and colorful.

Pedal disks

Cnidaria | Sea anemone polyps attach to substrates using this.

Siphonoglyph

Cnidaria | Ciliated tract that moves water into the gastrovascular activity to maintain the hydrostatic skeleton. Anthozoans have this.

Mesenteries

Cnidaria | Arranged in pairs. Some attach at the body wall at their outer margin, allows water to circulate between compartments.

Mesentrial filaments

Cnidaria | Tri-lobed. Bear cnidocytes, cilia that aid in water circulation, gland cells that secrete digestive enzymes, and cells that absorb products of digestion.

Pedal laceration

Cnidaria | Piece of pedal disk may break away from the anemone polyp and grow into a new individual.

Longitudinal Fission

Cnidaria | Two halves of an individual appear to simply move in opposite directions until it pinches into two individuals. Primary form of reproduction for many anthozoan species.

Corals

Cnidaria | Lack siphonoglyphs. When threatened, retracts into their protective exoskeletons.

Ctenophora

Characteristics

• Diploblastic or possibly triploblastic.

• Biradial symmetry.

• Gelatinous cellular mesoglea.

• True muscle cells develop within the mesoglea.

• Monoecious.

Comb rows

Ctenophora |

Colloblast

Ctenophora | Adhesive cells on tentacles that capture prey.