Phylum Annelida

segmented round worms

Phylum Annelida characteristics

true segmentation = metamerism

have a head, body (trunk), and tail = prostomium, peristomium, pygidium

tubular digestive system

protostome, coelomate, shizocoely

Phylum Annelida

Things continuous through whole body

digestive system

circulatory system

nervous system

Phylum Annelida

Things repeated in every segment

lateral blood vessels and nerves

nephridial organs

respiratory tissue (material/organs)

sometimes hearts

Class Polychaeta

Class of polychaete (bristle) worms

almost entirely marine

have paddle shaped structures on every segment (1 pair) = parapodia

have many setae

most cephalized

closed circulatory with respiratory pigment

Class Clittelata

Class containing earthworms and leeches

Class Clitellata

Subclass Oligochaeta

Subclass of earthworms

few setae

no parapodia

little cephalization

no gills

typhlosole - increased surface are for digestion and absorption

chloragogen cells- liver like

calciferous glands- control calcium and carbonate ion levels in blood

clitellum- used to make egg casings

Subclass Oligochaeta external fertilization reproduction

transfer sperm into another, goes into Seminole receptacle, after mating and separating clitellum makes sticky mucus and albumen (egg white) to feed embryo, sticks to sediment, worm backs out of it and deposits eggs and sperm into it

Class Clitellata

Subclass Hirudinea

characteristics like Oligochaeta

Subclass of leeches

no parapodia

clitellum- makes egg case

one pair of nephridium per segement

gonads and reproductive structures distinct and repeated in a few segments

Class Clitellata

Subclass Hirudinea

characteristics different from Oligochaeta

no setae

no hearts

anterior and posterior suckers

reduced amounts of segements

open circulatory

digestive system has cecum (has bacteria for digestion)

well developed temperature and chemosensory and light sensory structure

little regeneration

internal fertilization

Class Echiura

Class of spoonworms

body divided into 2 parts: proboscis (should be prostomium) and trunk

coelome has 2 parts - 1 prostomium, 1 in trunk

proboscis is extremly long and ciliated that helps to collect food and pick up surface debree (mud or organics from water) and push into mouth with cilia

trunk can be 40 cm, up to 1 meter or 1.5 m when prostomium extended

all marine

schizocoely, determinate, spiral, 4d cell

Class Echiura

Bonellia

males live permanently in female genital sack, fertilizes egg, planktonic larvae, trochophore,

lands on mud = female

lands on prostomium of female = male