Refers to a sponge's structure, regardless of its evolutionary relationship to other sponges. 

There are 3 grades: 

1) Asconoid

2) Syconoid

3) Leuconoid 

• Body wall not folded to form channels or chambers. 
• Choanocytes line only the central spongocoel. 
• Typically only a single osculum. 

• Infolding of the body wall forms choanocyte-lined channels that increase surface area, allowing for a greater number of chanocytes per body volume. 
• The narrower spongocoel, like the outer surface, is lined by pinacocytes.  

• Thick body contains numerous tiny chambers, each lined by a greater number of choanocytes, connected by a complex series of channels. 

1) Calcarea - Spicules made of CaCO₃ - A,S,& L

2) Hexactinellida - Spicules made of SiO₂ and six pointed

3) Demospongiae - Spongin fibers and/or SiO₂ spicules with 2,3, or 4 point - All L - 95% of known species

Sycon - Syconoid grade sponge C.S. 

A) Spongocoel lined with pinacocytes. 

B) Choanocytes lining chambers 

C) Ostia 

D) Mesophyl which contains gametes 

E) Pinacocytes lining exterior and spongocoel 

The glass sponges with long, 6 pointed, SiO₂ spicules.

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• Medusa stage is never present. 
• Polyps have a GVC divided by mesenteries that are lined with nematocysts. 
• Reproduction may be sexual or asexual. 
• The mesoglea contains mesenchyme cells. 

Ph. Cnidaria

Cl. Anthozoa  

Subcl. Hexacorallia

• Polyps have simple, non-pinnate tentacles, frequently in multiples of six, although numbers can vary from several to hundreds. 
• O. Actiniaria - The true sea anemones are non-colonial, (though may be clonal), lack a calcareous skeleton and have paired septa. 
• O. Scleractinia - The stony corals produce a calcareous exoskeleton secreted by epidermis. Polyps are colonial, but monomorphic, and share a common gastrovascular system. 

O. Actiniaria 

Parts of the Oral Disk 

• Tentacles of various sizes 
• Mouth 
• Siphonoglyphs, the heavily ciliated grooves that run from the mouth down the inside of the pharynx. - sweeps water down into the GVC.

1) Digestion 

2) Structure - GVC is filled with sea water to act as a hydrostatic skeleton. 

3) Movement - Opening and closing by filling it with water. 

Structure and Movement would aid from seawater, but digestion would be compromised because of the dillution of enzymes. 

Which muscles of a sea anemone are contracted and which are relaxed in order for it to flatten? 

To re-extend? 

• To flatten: the lingitudinal and sphincter muscles are contracted while the circumferential muscles are relaxed. 
• To re-extend: The circumferential muscles contract while the longitudinal and sphincter muscles relax. 

Threadlike tentacles posessed by some species of anemones that are used in feeding and defense. They originate inside the GVC along the edges of mesentaries (partitions of the GVC) near the aboral end. 

They can be rapidly forced out of the body when the animal is sufficiently disturbed through the mouth and cinclides - blister-like pores in the body. 

They contain elongated nematocysts. 

Ph. Cnidaria 

Cl. Anthozoa

Subcl. Octocorallia

Polyps with eight pinnate tentacles, most colonial. 

• Gorgonians - have an endoskeleton with a central protein rod surrounded by calcareous spicules. 
• Sea pansies and sea pens - fleshy, polymorphic colonies with calcareous spicules embedded in soft tissue. The colony is inflated by a hydrostatic skeleton generated by the primary polyp, which forms a central axis on which lateral polyps are arranged. 

Ph. Cnidaria 

Cl. Scyphozoa 

Life cycle dominated by a large, pelagic medusa usually includes a small benthic polyp (the scyphistoma). Many young medusae (called ephyrae) are formed by transverse sectioning (strobilation) of the scyphistoma. 

All but one class has pelagic medusa. The exception has a benthic, stalked medusa that remains attached to surfaces and is never free-swimming. 

Cl. Scyphozoa - Aurelia - the moon jelly

The epidermis and gastrodermis linning are true epithelia. Hard to distinguish between them and mesoglea. 

Manubrium - Short tube where the oral arms meet that leads to the mouth. 

Scyphistoma (solitary polyp) of Aeralia Cl. Scyphozoa

Strobila - the polyp of a Scyphozoan as it undergoes strobilation to produce medusae. 

Ephyra - the immature medusa of a Scyphozoan. 

Should be able to identify the developing rhopalia, stomach, oral arms, manubarium, and canal of GVC. 

Ph. Cnidaria

Cl. Cubozoa 

Box jellies with tetra-tentaculate anatomy. 

Fish-feeding = venomous 

"Comb-bearer" - gelatinous, planktonic carnivores. 

Swim using Ctenes - 8 longitudinal rows of specialized, compound cilia fused into flat plates. 

Differences between them and Cnidaria. 

   1) Movement with oral end forward (usually) 

   2) Ctenophores have muscle cells below the epithelium in the mesoglea 

   3) most are simultaneous hermaphrodites. 

Colloblasts - 

1) Cl. Tentaculata - Have two or more tentacles at some point in the life cycle. They are typically used for capturing plankton. 

2) Cl. Nuda - No tentacles (and no colloblasts). These animals eat other members of the plankton, opening their mouths wide and tearing prey items apart with big compound ciliary teeth. 

Triploblastic flat worms with ectoderm, endoderm; and mesoderm. 

Mesoderm in flat worms gives rise largely to loosely packed cells called parenchyma, which fills most of the body, as well as distince muscle bands. 

Acoelomate - Do not have a fluid-filled coelome. 

They also lack specialized respiratory structures and a circulatory system so the exchange of gases and metabolic wastes between cells and the outside world occurs by diffusion across the body wal. They have an incomplete gut with a mouth that serves for both feeding and defecation. 

Ph. Pltyhelminthes

Cl. Turbellaria

Mostly free living class consisting of O. Polycladida (large, marine flat worms) and O. Tricladida. 

Locate lumen at the center, mouth at its posterior end of the pharynx. And the pharyngeal cavity (the light space around the pharynx) into which the pharynx is drawn when not protruded. 

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Active, benthic predators with eversible sticky, entangling, or barbed/poisonous proboscis to capture prey. 

Rhynchocoel - Shared, derived character (along with proboscis) - fluid filled body cavity into which the proboscis is retracted.  

1) Enopla: possess a hard, piercing stylet at the tip of the proboscis; proboscis pore and mouth are joined as one opening; mouth opens anterior to the brain. 

2) Anopla: lacks a stylet on the proboscis; proboscis pore and mouth are separate; mouth opens posterior to the brain. 

The cells that form new stylets. 

Mouth - large ventral slit or cleft. 

Cephalic slits - either side of the head open into small chambers. 

: Cilia circulate water past chemosensory organs within the slits. 

Proboscis pore: a mid-ventral opening anterior to the much larger mouth. 

"thread-body" - most abundant multicellular animals on the planet, with as many as 4 million/square meter in some marine habitats. 1/2 free living.

Very round in cross section. 

Pseudocoelom derived from blastocoel - it is not lined by epithelium and functions as a hemocoel (blood cavity). 

High internal pressure of the body cavity is resisted by a chitonous cuticle reinforced by collagen fibers 

Sinusoidal locomotion. Only longitudinal muscles 

Molting cuticle. 

Longitudnal nerve cords with prominent ring around the esophagus. 

Muscles extend to nerve cords!

Metabolic wastes excreted mostly by diffusion through body wall. 

Osmoregulation sometimes accomplished by an excretory gland and canal system - esp in freshwater. 

Include nematoda 

Features include: 

1) a pseudocoelom 

2) a thich, extracellular cuticle that is molted during development

3) The loss of locomotory cilia (even sperm move like amoebae!) 

4) The loss of circular muscles, 

5) Eutely - a fixed # of cells within the body. 

6) A ring-shaped brain that encircles the anterior foregut--hence, the superphylum name Cycloneuralia

Under heavy revision!

Cl. Polychaeta - Primarily marine, 70% Parapodia often covered in setae. Errant or sedentary. 

• F. Siboglinidae - extremesists in cold methane seeps or hydrothermal vents. Chemosynthesis through bacteria in trophosome. Segmented at posterior end.

Cl. Clitellata - Clitellum - specialized multi-segmented body region that is a shared derived character for this class - secretes cocoon in which reporduction and or development takes place. All hermaphroditic.

• Subcl. Oligochaeta - Lack parapodia, few setae, segmented. fresh, marine, or terrestrial. (earthworm) Peristaltic waves = locomotion
• Subcl. Hirudinea - The leeches - lack parapodia, no setae - can appear segmented externally but the coelome is not subdivided internally. Most are ecto parasites. 

Cl.(??) Echiura - Lack parapodia, not segmented as adults, posses only a pair of setae on the body surface. use non-retractable proboscis for deposit feeding

Cl.(?) Sipuncula - Lack parapodia, chaetae, and any trace of segmentation. Fully retractable, eversible introvert at the anterior end of the body with a mouth and tentacles powered compensation sacs.   

F. Nereis 

Jaw

Sensory Tentacles

Palps

Prostomium

eyes

peristomium

Tentacles  

Nereis parapodium 

1) Dorsal Cirrus 

3) Top= Noto- / Bottom = Neuropodium, Chaetae

6) aciculae

Nereis C.S. 

A) Ventral Long Muscle 

B) cuticle and Epidermis 

C) Coelom

D) Ventral Nerve cords 

E) Ventral Blood vessel 

F) Gut lined with gastrodermis 

G) Dorsal Blood vessel 

stringy Circum muscle 

Mesenteries dividing the coelome 

Acicula - the thick chitinous supporting fibers within the parapodia 

Nereis is an herbivore. 

Errant, burrowing carnivore with reduced head and parapodial structures that relate to its burrowing lifestyle. 

Eversible pharynx and venomous fangs. 

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Errant predators known as the "scale worms" because of their soft scales called Elytra, on the dorsal surface. 

Similar to Nereis with respect to large parapodia, lack of body regionalization, and prominent sensory structures on the head. 

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Large, errant, slow moving predators known as sea mice.

Live on soft muddy bottoms where they plow through sediment and consume small animals. 

Body covered with elytra that are hidden behind a dense mat of poisonous, irridescent setae, which can be erected when in danger like a porcupine or echidna. 

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Surface deposit feeders, sedentary. 

Builds soft mud tubes on surfaces or in sediment and sends out tentacles to transport sediment particles back along ciliated grooves on the tentacles. 

Bright-red gills 

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