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1. ANNELIDA
(Segmented Worms)
Nolie Calidro Gerardo
Nicole Calidro
Mariano Marcos State University
COLLEGE OF TEACHER EDUCATION

2. • Annelida came from the Latin word “annelus” means little
ring
• Over 12,00 known species are grouped into 3 classes:
Polychaetes, Oligochates and Hirudinea
• The most highly advanced and most successful of the
various “worms phyla
• Symmetry bilateral; three germ layers
• Soft bodied animals in which the large fluid filled coelom
serves as a hydrostatic skeleton

3. 3 MAJOR CLASSES
CLASS POLYCHAETA
• From the Greek word poly (many) and chate (spine or
bristle)
• Largest class of annelids with over 8,00 species
• Live in ocean
Features
• Long, slender, greenish body is rounded and flattened
vertically and composed of 200 or more similar somites
• Distinct head is formed by prostomium and peristomium

4. • The protosmium bears 2 short protosmial tentacles,
pulps and eyes
• The peristomium surrounds the ventral mouth and
carries 4 pairs of peristomial tentacles
• The anus is the first somite on which are two soft
sensory anal carri
• The body was covered by cuticle
• Within the body wall was coelemic cavity

5. EXAMPLES

6. Digestive System
• Includes mouth, pharynx, esophagus, stomach, intestine and
anus.
Circulatory System
• Comprised a dorsal and ventral vessel
• The plasma is red containing dissolved hemoglobin and
amoebocytes
• Circulation results from peristaltic contraction of dorsal
vessel

7. Respiration
• Effected by capillaries in the parapodia and body wall
Excretion
• Performed by paired nephridia
Nervous System
• Includes brain, nerves to the bead and tentacles, connectives
to the mid ventral nerve cord and a pair of ganglia and
lateral nerves
Reproduction
• Sexes are separate and gonands are present only on
breeding season
• Fertilization occurs in the sea
• Allows epitoke

8. SUB CLASS
1. Errantia
• Those are free living and crawl or swim
• Have body of similar segments with well developed
paopodia
• A muscular eversible proboscis with teeth or jaws
• Distinct head and organs
Alitta succinea
(known as the pile worm or clam worm)

9. 2. Sendentaria
• Those confined permanently to tubes, often with
the body divided into 2 or more regions or tagma
• Without a protrustible proboscis with jaws
• With a reduced head
Cirratulus cirratus

10. 3. Archiannelidda
• Small in size; segmentation chiefly internal
• Parapodia and setae usually absent
• Nervous system in epidermis; usually dioecious;
gonads numerous
• Marine
Polygordius (polychaete genus)

11. CLASS OLIGOCHAETA
From the Greek word oligos (few) and chaeta (spine), have few
setae per segment
• Live in fresh water and moist soil
• 3,100 species
External Features
• The body is long and cylindrical bluntly tapered at each
end
• There’s no distinct head
• The mouth is the first somile and the anus is the last somile
• The clitellum that secrets material forming cocoons to
contain eggs

12. • A mature worm is divided into 115 200 somites
• Dorsal pore connect the body cavity and
exterior
Earthworm

13. Internal Structure
• The space between of the two concentric tubes, the outer
body wall and the digestive tract is the body cavity or coelom
• The coelom and all organisms within it are covered by
peritoneum

14. Digestive System
• Consist of the mouth, pharynx, esophagus, crop, intestine
and anus
• The intestine is thin walled and bulges laterally in each
somile and its dorsal wall carries an infolded thyposole
for absorption of food

15. Circulatory System
• Blood consist of fluid plasma that contains
amoebocytes
• Plasma is colored red by hemoglobin
• Blood circulate in a system of closed blood
vessels

16. Respiration
• No organized respiratory system
• Through epidermis
Excretory System
• Every somile except the first three and last has a pair
of nephridia
• Nephridia act much like tubules in human kidney

17. Nervous System
• A pair of supra pharyngeal cerebral ganglia, the
brain
Reproduction
• Monoecious; both male and female sex organs are
ventral and anterior
• Males sex organs: 2 pairs of minute testes, 2 sperm
funnel, ductus efferens, ductus deferens, malepore and
seminal vesicles
• Female sex organs includes ovaries, oviduct funnels,
oviduct and seminal receptacles

18. ORDER
• Lumbriculida
Lumbriculus variegatus

19. • Monilogastrida
Moniligaster

20. • Haplotaxiada
Sub-Orders
A. Haplotaxina
B. Tubifiana
C. Lumbricana
haplotaxis
Tubifex
megascolides

21. CLASS HIRUDINEA
• Aquatic or terrestrial worms
• Have enlarged terminal suckers for locomotion
and attachment
• Most are fluid feeding
• Blood sucking group( most)
• Scavengers, predators, or parasitic
• The body is divided into 34 somites
• 500 species

22. Features
• The body of a leech at rest is long or oval in outline
• Usually flat dorsoventrally and very flexible maybe
stretched
• Posterior end is a rounded sucker
• Another sucker surrounds the mouth at the anterior
end in many species

23. Digestive system
• Includes the mouth, pharynx, short esophagus, 20 pairs of
lateral caeca, a slender intestine, short rectum
Circulatory System
• Longitudinal sinuses , dorsal, ventral and lateral, with many
cross sections
• Pulsations in some of three cause the blood to circulate

24. Respirations
• A network of capillaries beneath he epidermis
Excretion
• It pairs of peculiar nephridia
• Sometimes branched and sometimes have closed
nephrostomes
Nervous Sysem
• Pair of dorsal ganglia and paired connectives to the
ventral nevre cord
• Four of the anterior ganglia
• Seven at he posterior end are fused

25. Reproductive Sytem
• Male reproductive system includes 4 to 12 pairs of testes
beneath the crop, ductus deferens running anteriorly
• 2 ducts enter a median penis to which accessory glands
connect
• The penis is within the general pore
• Female reproductive system includes 2 ovaries and oviducts
joining a single albumen gland and a median vagina that
opens just behind the male pore
• Sexes are united

26. Image Source: Google Images