PROTOZOA
Kingdom protista
Protista coined by Haeckel.
Unicellular, eukaryotic organism
Photophyta
Dinoflagellate----------------->motile, biflagellate
Eg. Catenella(Poisonous), Noctiluca, Catenella (Noctiluca, Catenella are bioluminescent)
Also called fire alga.
Diatoms----------------->Non-motile, source of food, water pollution indicator, eg. Nevicula, Amphipleura
Euglenoids----------------->motile, biflagellate
Absence of cellulose
Both auto and heterotrophy
Eg. Euglena, Rhabdomonas
Slime moulds
Protistian fumgi because they donot have chlorophyll and cellulose cell wall.
Eg. Fuligo, Tubifora, Lycogala
Euglena viridis is link between plant and animal.
Protozoa
Protozoa coined by Goldfuss.
Contractile vacuole present in fresh water forms and absent in marine and parasitic form.
Respiration and excretion through general body surface.
Protozoans are ammonotelic.
Class
- Rhizopoda
- Flagellata
- Sporozoa
- Ciliata
Rhizopoda----------------->Locomotion by pseudopodia
Flagellata----------------->Locomotion by flagella
Sporozoa----------------->Endoparasite exclusively locomotory organ absent.
Ciliata----------------->Locomotion by cilia
Giardia is bilaterally symmetrical but other are assymetrical.
Body nacked without definite shape in rhizopoda.
Monocyst----------------->Parasite in seminal vesicle of earthworm.
Ceratium and Noctiluca are bioluminescent protozoans.
Amoeba proteus
Discovered by Rosenhoff
Plasmalemma is excretory, protective and respiratory in function.
Amoeba is not able to digest fat.
Contractile vacuole of amoeba is analogous to uriniferous tubules of frog.
Sol-gel theory of amoeboid movement was given by Hyman.
According to this theory amoeboid movement is due to change in viscosity of cytoplasm.
Amoeba ingest food by import, circumfluence, circumvallation or invagination.
- Circumfluence----------------->Less active or motionless organism ingestion
- Circumvallation----------------->Engulfment of active prey
Contents in food vacuole is first acidic and then alkaline.
Kala-azar is caused by protozoa Leishmania donovani and transmitted by sand fly.
Contractile vacuole of Amoeba and some other protozoa are related with osmoregulation.
Euglena belongs to protozoa.
Entamoeba histoytica causing dysentery transfers through housefly that resides in colon of man. Quadrinucleate cyst is it’s infective stage.
Amoeba reproduces by sporulation in unfavourable and by fission in favourable condition.
Giardia lamblia called Grand old man of intestine resides in duodenum and upper part of jejunum that has binucleated racket shaped feeding stage(trophozoite) and quadrinucleated oval shaped infective stage(cyst).
E. gingivalis and E. coli are non-pathogenic commensal living surface of teeth and gum and colon respectively. E. gingivalis doesnot form cyst and it’s adult is called trophozoite.
Trypanosoma gambiense, cruzi and rhodensia cause African sleeping sickness, American sleeping sickness/ chagas disease and rhodensian fever respectively. Vector of trypanosome is tsetse fly.
Leishmania tropica and Mexicana cause cutaneous leishmaniasis(oriental sore). Leishmania brasiliensis cause mucocutaneous leishmaniasis in south Africa.
PORIFERA
Study called parazoology
Grant termed Porifera.
Ellis established animal nature of sponges and Wilson gave regeneration in Sponges.
Solitary-------------------->Sycon
Colonial-------------------->Leucosolenia
Called sponges and republic of cells.
Unique feature of porifera is canal system.
Diploblastic ------------------->Outer pinacoderm and inner choanoderm
Pinacoderm has multi-nucleated flattened Pinacocytes and uninucleated tubular Porocytes.
Coanoderm have flagellated choanocytes. Between pinacoderma and choanoderm is mesenchyme/mesohyl containing collagen fiber, spicules and amoebocytes.
Amoebocytes(wandering cells)
- Archaeocyte-largest, totipotent cell
- Trophocyte- Nurse cell, supply nutrient to developing cells
- Collencytes-uninucleated, secrete collage fibre
- Scleroblast- Secrete spicules and sponging fibres
- Germ cell, gland cell, chromocyte, etc.
Canal system Ascon(Leucosolenia)
Sycon(Sycon)
Leucon/Rhadon type(Euplectella, hyalonema, demospongia)
Sponges are filter feeder.
Ascon type path of water/food.
Dermal ostia------------>Gastral ostia-------------->Spongocoel----------------->Osculum
Digestion of food partially in choanocyte and partially in wandering amoebocyte.
Reproduction asexual--------->Fragmentation, gemmule or buds
Sexual----------> by ova and sperm
Poriferans are protogynous(female mature before male) or Hermaphrodite.
Development indirect.
Larval forms are
- Amphiblastula-hollow-eg. Sycon
- Parenchymula-Solid-eg.Leucosolenia
Sponges classes
- Calcarea- ascon/sycon(eg. Sycon/Leucosolenia)
- Hexactinellida-sycon/leucon-eg.Euplectella, Hyalonema
- Demospongia-Leucon(eg. Spongilla, Euspongia)
Water current through the body of sponges is maintained by Choanocytes.
Euspongia--------->Bath sponge(sponging fibres left after drying)
Cliona----------->Boring sponge(harmful to pearl/oyster industry)
Euplectella---------->Venous flower basket
Porifera are invertebrates without neurons.
COELENTERATA
Leukert coined the term Coelentrata and cnidaria by Hyman.
All the cnidarians are radially symmetrical except sea anemone , which is biradially symmetrical.
Acoelomate , tissue grade of body organization are some characteristics of this phloem.
Solitary (Hydra ) or colonial( Obelia) , sedimentary ( Obelia) , or free swimming (Aurelia)
Individual are known as zooids.
Polymorphism is characteristics of phylum coelentrata.
Mouth is surrounded by tentacles ( solid in Obelia , Hollow in hydra ).
Rhopallium or tentaculocyts are modified tentacles ( serve as organ of equilibrium and maintain water circulation)
Larval stage of Planula ( Obelia ) and Euphra ( Aurelia )
| Hydrozoa( water + animal) | Anthozoa( flower + animal) | Scyphozoa ( cup + animals) |
| Poly and medusa form both present | Poly form only | Medusa form only |
| Velum in medusa | Velum is absent in medusa | No velum in medusa except for jelly fish |
| Diploblastic | Triploblastic | Triploblastic |
| Hydra , Obelia | Corals , sea anemone | Aurelia , Rhizostoma |
Hydra –
poly form
No segmentation
Termed hydra by Linnaeus due to great power of regeneration.
Proximal end or basal end part closed and flat called pedal or basal disc and distal end elevated into a conical hyptostome or manbrium with mouth at its apex.
- Hyptostome bear 6- 10 tentacles which help in locomotion and feeding.
- Growth zone of hydra is located just below tentacles.
- Central cavity is coelonteron or gastrovascular cavity that serves for digestion and circulation.
Chlorohydra viridissima is green due to symbiotic association with zoochlorella not chlorophyll.
Endoderm or gastroderm is thicker than epidermis or ectoderm.
Cnidoblast and germ cell are absent in gastroderm .
- Interstitial cell forms any other kind of cell.
- Interstitial cell absent in epidermis of pedal disc and tentacles .N
- Nerve cell first seen in animal kingdom in hydra.
- Nervous system consist of non synaptic nerve net.
Hydra can digest all types of food except starch .
Hydra moves fast during somersaulting ( most common)
Walking resembles cuttle fish locomotion so called cuttle fish movement . Gliding is slowest method of locomotion.
- Asexual reproduction by budding (favourable) and sexual by synagamy ( unfavourable)
- Hydra regenerates by morphollaxis i.e every fragment will grow into complete hydra.
- Hydra has single ovary ( in aboral region) and many testes in oral region.
- Protandrous ( male mature faster than female)
- No free swimming larva
- Plematohydra is hydra with longest tentacles .
- Protohydra is hydra without tentacles with a basal disc prolonged into a stalk.
PLATYHELMINTHES
Dorsoventrally flattened
Gegenbaur termed Platyhelminthes.
Platyhelminthes are triploblastic.
Alimentary canal incomplete or absent.
Skeletal, respiratory and circulatory organs absent.
Excretory organs-----> Protonephrida or solenocyte or flame cell.
Anaerobic respiration in internal parasite like Taenia.
Rhabdites (Planaria and Turbellaria)
Ootype surrounded by Mehli’s gland/ shell glands.(Mehli’s gland’s secretion lubricate the passage.)
Parasitic flatworms have body body with cuticle ---------------> Tegument
Cross fertilization in trematodes and self in cestodes.
Cestoda--------------->Digestive system absent, eg. Taenia
Trematoda-----------> Well developed digestive system. Eg. Fluke
Turbellaria-------------------> eg. Planaria, Convoluta, Eddy worm
All trematodes are hermatodite (both ♂ and ♀ in same individual) except blood fluke.
Flattened leaf like body-----------------> trematods.
Planaria(Dugesia)--------->Nocturnal
Gregarious(live in group)
- Remarkable power of regeneration
- Epimorphosis and Morphollaxis
- Development is direct and ectolecithal, cleavage-spiral
Faciola Hepatica(Sheep liver fluke)
Primary host(mammal)------>Pathogenic
Secondary host(snail)-------->Harmless
- Liver rot- Single sheep may contain about 200 flukes as a result it’s liver stops to wor.
- Excretion by flame cells which are connected to excretory canal by their canaliculi.
- Laurer’s canal appear during breeding season.
- Male reproductive system-Two testes tendem position (lying one behind the other).
- Female reproductive system- One ovary, an oviduct, vitelline glands, Mehli’s gland/ Shell’s gland situated on right part of body.
- Miracidum(Snail)-------------->Sporocyst-------------->Cercaria(Heart shaped bifid intestine) -------------->Metacercaria(infective mammal) @MiSRaCeMe
- Redia develops from sporocyst parthenogentically.
- Faciola cannot complete its lifecycle in absence of water.
- Polyembroyny----------------->Faciola Hepatica
- Faciola exhibits both alternation of generation and alternation of host.
Schistosoma(Blood fluke)------------------>Biharzia
- Female longer slender nad lodged in the gynaecophoral canal of male.
- S. haematobium cause kidney damage.
- Redia and metacercaria stage absent.
- Primary host(man), secondary host(Balinus and other snail.)
- Swimmer’s itch(severe cercarial dermatitits).
- Treated by prazi-quantal.
Taenia solinum(pork)
Taenia saginata(beaf)------------------>No hook
Cysticerus-----------------------> larva
Strobila(Main body)
- Male reproductive system for 200 segment and back 100 to 150 segment have both male and female reproductive organs.
- Gravid segment is last segment with branched uterus containing fertilized eggs.
- Apolysis-------->Last gravid segment detach and fall
- Tegument contain CaCO3 and bear microvilli(tegument-covering).
- Cysticercosis is more dangerous than taeniasis.
- Bladderworm infected pork-------> Measly pork.
Diphylobothrium latum(Fish tapeworm)------longest in Human\
Hymenolepsis nana(Dwarf tapeworm)----------------Shortest in human
Echinococcus granulosus(Dog tapeworm)------------Human as intermediate host
Oncosphere(pass through faeces of man)----------->Hexacanth(has 6 hooks)------------------>Cystecercus(Bladderworm)_
NEMATHELMINTHES
- Pseudocoelomate
- Epidermal syncytial/ coenocytic and covered with cuticle.
- Eutely: Number of cells in different body parts fixed.
- Circular muscle, segmentation and cilia absent.
Amphid→ Olfactory receptors (in mouth)
Phasmid→ Sensory papillae (in anus)
| Phasmida(Secernetea) | Aphasmida(Adenophora) |
| → Caudal sensory organ | → Absent |
| (Phasmid) present. | |
| → Excretory system absent. | → Renette cell. |
Ascaris lumbricoides( Round Worm)
►Endoparasite of jejunum.
► Male→ Smaller, curved tail, pineal setae in cloacle aperture.
→ Have cloaca with 50 pairs of pre cloacle apertures and 5 pairs of post cloacal apertures.
→ Ventral surface bears fifty pairs of pre-anal and five pairs of post anal papillae.
► Female→ No cloacle aperture, has straight posterior end.
► Circular muscle layer is absent in Ascaris.
► Salivary glands do not occur in Ascaris.
► Single H-shaped excretory cell or renette cell.
► Testes and ovary are telogonic (only anterior part is functional).
► Sperm → Tailess, asymmetrical and amoeboid. Egg shell dissolved by pancreatic juice.
► Moulting occurs four times(1 outside human body, 2nd and 3rd in lungs and 4th in intestine.
► Larva is called rhanditoid or rhabditiform.
► Nerve ring → Nine ganglia attached.
► 2nd stage larva infective which enters the lungs and 4th stage larva comes out of the lungs.
► 4th stage larva comes out of the lungs.
Loa loa (Eye worm)
► Vector is mangofly.
► They are seen moving beneath the conjunctive so called eye worm and cause conjunctivitis.
► Adult live in sub-cutaneous tissues of body and migrate freely.
Dracunculus medinensis (Guinea worm)
► Called “fiery serpent”, “medina worm”, “guinea worm”.
► Digenetic, intermediate host is Cyclops or water fleas transmitted through contaminated water and is viviparous.
Anclyostoma duodenale (Hook worm)
► Monogenetic (no intermediate host), found in small intestine of man and feed upon blood.
► Number of moults in life cycle of Ancylostoma duodenale is 4.
► Infective stage is Filariform larva (3rd stage juvenile is infective).
Wuchereria bancrofti
► Filarial worm.
► Lives in lymph vessels and lymph glands in lymphatic system of human.
► Digenetic: Man as primary host and female Culex mosquito as secondary or intermediate host.
► Infective stage is microfilaria (3rd stage infective). Filaria is a helminth.
►Route for Ascaris:
Outside→ Intestine → Liver → Lungs → Trachea → Oesophagus→ Intestine.
ANNELIDA
Earthworm is given separately.
►Comprises of segmented worms exhibiting metamerism.
► The term “Annelida” was coined by Lamarck.
► Chaetopterus and Polynoe are bioluminescent annelids. Trochophore larvae is found in Annelid.
► Trocophore larvae is found in Annelid.
► Sea mouse belongs to Annelida.
► The body of Hirudinaria consists of 33 segments.
► Botryoidal tissue is related to leech.
► Hirudin secreted by salivary glands is present in saliva of leech.
| Polychaeta | Oligochaeta | Hirudinea | Archiannelida |
| -Parapodia (locomotion) | - Setae | - Suckers | -Absent locomotary organ |
| - Long & Numerous Setae. | - Small & fewer setae | - Absent | - Usually absent |
| -Indirect Development With troco- Phore larva. | - Direct development | - Direct development | - Indirect with trochophore larva directly. |
| -Clitellum (Absent) | - Present | - During breeding season developed. | ─ |
Polygordius→ Living Fossil
Nereis→ Sand Worm or rag worm
ARTHROPODA
► Largest phylum in animal kingdom.
► Number of segments in arthropod is always fixed.
► Segmentation in arthropods is metameric but external only(this type of merismetism is called tegmatization)
► Chitinous plates present over the body called Sclerites. Cuticle undergoes periodical ecdysis.
► Arthopods are haemocoelomate, open circulation.
► Jointed appendages.
► Colorless blood contain only WBC.
Terrestrial→ Malphigian tubules, uricotelic.
Aquatic→ Green glands, uricotelic, solid, double, ventral nerve cord.
►Vision→ Mosaic(Compound eyes)→ Unit structure→ Ommatidia
→ No image(Simple eyes)→ Unit structure→ Occeli (expect- Arachnida)
► Biiting and chewing type→ Cockroach, Grasshopper
► Chewing and lapping type→ Bees, Wasp
► Piercing and sucking type→ Mosquito, Bug, Aphids.
► Sponging type→ Housefly
► Siphoning type→ Butterflies & moths
| Centipede | Crab | Spider | Housefly |
| -Myriapoda | - Crustacea (Hint: Cr-Cr) | - Arachnida | -Insecta |
| -Head+trunk | - Cephalothorax +abdomen | -Prosoma+ Ophistothoma | -Head+tho- rax+abdomen |
| -Many pair | - 5 pair | - 4 pair | - 3 pair |
| (Walking leg) -1 pair(Antenna) | - 2 pair | - No antenna | - 1 pair |
| - Trachea | - Gills | - Book lungs | - Trachea |
| &trachea | |||
| -Malphigian Tubules | -Maxillary/ Antennary/ Green gland | - Coaxal gland | –Malphigian tubules |
►Perpatus→ Connecting link between Annelida and Arthropoda
►Limulus→ Living fossil (Horse shoe shaped, King Crab)
► Insecta only contain mouth parts and salivary gland.
► Spider→ Excretion→ Guanotelic
► Crustaceae→ Ammonotellic
→ Only contain Statocyst
► Gland forming thread in spider→ Spinneretes
► Black widow spider→ Eats its partner after copulation.
► In Prawn→ Only oxygenated blood flows.
► Myriapoda→ Chilopoda (Centipede) [ 1st pair of leg→Poison claw]
→ Diplopoda (Millipede) [ 1st pair→ No leg]
Group of insects based on development:
| Type | Development Metamorphosis Larva&Pupa Eg Remarks | |||
| -Ametabolous | - Direct | - Absent | - Absent -Silverfish -None | |
| -Paurometabolous -Direct | - Gradual | - Absent -Cockroach -Nymph | ||
| - Hemimtabolous | - Direct | - Incomplete | -Absent -Dragonfly -Naids | |
| - Holometabolous -Indirect | -Complete | -Present -Mosquito -None |
► Behaviour: Solitary- Scorpion, Cockroach, Spider
Colonial- Honey bee, Ant, Aphid, Termite, Wasp
Grouped- Grasshopper, Prawn, Crab
Gregarian- Locust
Cockroach:
► Nocturnal, Cursorial, Omnivorous
► Head(6 segments fused), thorax(3 segments fused), Abdomen(11 young, 10 adult).
► Vision→ Mosaic (2000 compound eyes)
► Omatidium→ Aposition type
► Wings arise from meso and meta thorax.
► Male→ 9th segment→ Anal style(9th sternum)
→ Mushroom gland or utricular gland
→ Phallic gland or conglobate gland is accessory gland that helps to form spermatophore that opens near male genital pore.
→ Male genital pore is surrounded by phallomers.
► Both male and female cockroach has anal cerci in 10th segment that helps in hearing.
► Female→ Collateral glands of female cockroach help in formation of ootheca.
► Rectal papillae of cockroach corresponds to typhlosole of earthworm.
► Haemolymph→ Blood (no respiratory pigment)
►Heart→ 13 chambered.
► Circulation→ Contraction and relaxation of alary muscle. Blood donot carry O2.
► Maximum digestion occurs in crop.
► Egg of cockroach is centrolecithal.
► Arolium→ Adhesive organ
►Locomotary organ→ Thorax
► Abdomen sternum→ Absent in 10th segment.
► Male→ All nine sterna visible but only seven in female.
► Cockroach has true coelom only in embryonated stage.
► Pseudopenis is found in left phallomere in cockroach.
Housefly:
► Saprophagus
► Larva headless and legless called grub or maggot(13 segments)
►Head consists of a pair of compound eyes(4000 omatidia), 3 ocelli and 2 antenna.
► Head bends downward (hypognathous).
► Labium is most developed mouth part and modified into long proboscis.
►Imago is young fly. It possesses a blood filled bladder like structure called “ptilinum”.
► Pulvilli is adhesive as arolium in cockroach.
Honey bee:
► Ernest spytzner recognized bee dance.
► Nurse bees form royal jelly.
► Round dance→Near food source.
► Waggle dance→Large distance food source, give direction.
► Fertilized egg→ Queen and workers.
►Unfertilized egg→ Drones(male)→ Parthenogenically developed
Silk worm:
► Nocturnal
► Study→ Sericulture
► Male dies after copulation, female dies after laying eggs.
► Egg → Larva → Pupa → Adult
Moult 4 times →Enclosed inside cocoon.
Develop silk gland →Silk obtained from cocoon.
Silk gland→ Modified salivary gland
► Natural silk contain nitrogen.
► Common→ Bombyx mori(seri-silkworm) →feed on mulberry leaves.
Mosquito:
► Nocturnal
► Head→ A pair of compound eyes, a pair of antenna, mouth part.
→Mandible absent in male, developed in female.
→ Pedicel of antenna bear Johnston organ(Sensitive to vibration).
[Note: Jacobston’s organ→In rabbit]
→ Female has cerci in 10th abdominal segment.
► Aedes→ Dengue fever/ Yellow fever/ Chikungunya
►Culex→ Filarial fever
► Anopheles→ Malarial fever/ Chikungunya
► Larva of mosquito→ Wriggler
► Pupa of mosquito→ Tumbler
| Anopheles | Culex |
| Egg- Singly, Horizontally, BoatShaped, 40-400 in clean water.water. | - In Cluster, Vertically, Cigar Shaped, 200-400 in dirty |
| Larvae- Surface feeder, Headhead. Parallel. | - Bottom feeder, Angular |
| Pupa- Green, Short Respiratory Trumpet. | - Colorless, Long Respiratory Trumpet. |
| Adult- Wing spotted, slender body. | - Wing uniform, Well built body. |
MOLLUSCA
Gastropods are only asymmetrical due to twisting called torsion.
Neopilina is only segmented mollusa. (also living fossil).
Circulatory system is open except cuttle fish.
In unio, oldest and thickest part of shell is umbo.
Unio is filter feeder.
Pallial cavity -------------->Glandular fold of body
Buccal cavity has a rasping organ called radula which is armed with transverse rows of chitinous teeth. Each row contains 7 teeth. Radula is provided with odontophore(Helps in straining of food.)
Respiratory pigment Haemocyanin (Cu containing) dissolved in plasma. Blood is blue in colour and contain amoebocytes.
Excretion by a pair of kidneys/ organ of Bojanus and pericardial gland or keber’s gland.
Unio has green gland(digestive gland). Green gland is analogous to liver of vertebrates.
Statocyst------------->maintain equilibrium of body
Osphradia------------->test chemical nature of water
Veliger is larva of marine pelecypods.
Glochidium is larva, an ectoparasite and attach to gills of fish.(Larva of Unio).
| Character | Shell | Foot | |
| Aplacophora | Epidermis secrete aragonite | Absent | Absent |
| Polyplacophora | Called Chitons | 8 piece | Muscular |
| Monoplacophora | Segmentation | Single cap like | Flat |
| Gastropoda | Torsion | Single cap like | Flat muscular |
| Pelecypoda or Bivalvia | Shell is bivalve | No in foot | Laterally compressed |
| Scaphopoda | Called tooth shells | Single tusk like | For digging |
| Cephalopoda or Siphonopoda | Ink gland | Shell(External—Nautilus) (Internal—Sepia) (Absent—Octopus) | On foot as arms |
Architeuthis(Giant Atlantic Squid) is the largest of all invertebrates.
In cephalopoda locomotion is by siphon jet system.
Teredo (shipworm) destroy wood in water.
Pinctada vulgaris (pearl oyster)-------------->pearl secreted by columnar epithelial cell of mantle.
Father of pearl industry is Mikimoto.
Trocophore larva occur in Annelida and Mollusca.
Neopilina is connecting link between annelid and mollusks.
Examples
Sea anemone(Doris)
Sea hare(Aplysia)
Limax(Slug)
Elephant’s tusk shell(Dentallium)
Solen(Razor shell)
Cuttle fish(Sepia)
Octopus(Devil fish)
Loligo(Squid)
Helix(Garden snail)
ECHINIDERMATA
► Echinodermata coined by Klein.
► Exclusively marine deuterostomes.
► Benthic (bottom dwellers) except sea cucumber(pelagic)
► Mostly free living except sea lilies.
► Echinoderms have no brain.
► Digestive tract complete except in Brittle star.
► Bilaterally symmetrical(larva), radially symmetrical(Adult).
► Sea urchin has masticating organ (Aristotle’s Lantern).
► Water Vascular System connected to outside through a perforated plate called madreporite. (Madreporite canal also called stone canal).
► Locomotion by tube feet.(Of ambulacral or water vascular system)
► Ring canal lined with Tiedman’s body or Racemose gland that helps in formation of lymphocytes.
► Circulatory system open type, heart absent.
► Blood doesnot contain respiratory pigment, respiration by tube feet.
► Cleavage is radial and indeterminate and development is indirect, eggs are homolecithal.
► Autotomy, Evisceration(vomiting of viscera) and Regeneration(Epimorphosis) well developed.
► Echinodermata→ Pelmatozoa→ Crinoidea
→ Elutherozoa→ Asteroidea
→ Ophiuroidea
→ Echinoidea
→ Holothuroidea
► Larva of Holothuroidea → Auricularia
Asteroidea → Dipleurula, Bipinnaria, Brachiolaria
► Starfish is benthonic, nocturnal and exhibits autotomy and has great power of regeneration.
► Presence of pinna like structure called pedicllariae that protects the skin gills. (Unique feature)
► No pedicellariae in Holothuroidea, Ophiuroidea.
► No arms in Echinoidea and Holothuroidea.
► Crinoidea donot have madreporite.
► Pumatozoa are sedentary and Elutherozoa are free moving echinoderms.