HALISTEMMA

CLASSIFICATION OF HALISTEMMA

PHYLUM :- COELENTRATA (Tissue grade, diploblastic and acoelomate. )

CLASS :-  HYDROZOA  (The hydroids and craspedote medusa )

ORDER :- SIPHONOPHORA (Polymorphic colonies without perisarc.)

SUB-ORDER :- PHYSOPHORIDA (Upper end of colony contains float or pneumatophore.)

FAMILY :- PHYSONECTAE (Pneumatophore small. It is followed by a stem bearing column of swimming bells.)

GENUS :- Halistemma

GEOGRAPHICAL DISTRIBUTION

  • Found in Mediterranean and other seas.

HABIT AND HABITAT

  • Halistemma is colonial, pelagic and highly polymorphic siphonophore with complex zooids.
HALISTEMMA

GENERAL CHARACTERSTICS OF HALISTEMMA

  • Entire animal comprises of pneumatophore, swimming bells and simple cormidia in floating axial stem. 
  • Small pneumatophore or float represents first part of the stem which secretes gas to keep colony up in water. 
  • Float is followed by several pairs of closely-set, transparent medusa-like, swimming bells or nectocalyces or nectophores.
  • Below nectocalyx, the axial stem gives at regular intervals several closely-set individuals, called as cormidia.
  • Each cormidium contains coenosarc bract or bydropbyllium gastrozooid, large dactylozooid, male gonozooids, larger female gonozooids with eggs and tentacles with batteries of nematocyst. 
  • Nematocysts are very much elongated measuring 1-12 mm. 
  • Fertilization external life-history includes Planula larva.
HALISTEMMA

IDENTIFICATION

  • The animal has several pairs of medusae like swimming bells and all above characters and hence it is Halistemma.
HALISTEMMA
HALISTEMMA
OUR POSTS
  • WHALE (BALAENOPTERA)​WHALE (BALAENOPTERA)​
    WHALE (BALAENOPTERA)​ CLASSIFICATION OF WHALE (BALAENOPTERA)​ PHYLUM :- CHORDATA (Notochord, dorsal tubular nerve cord present and gill slits present) Group :- CRANIATA (Definite head. Cranium with ...READ MORE
  • ERINACEUS : HEDGEHOGHEDGEHOG (ERINACEUS)
    HEDGEHOG (ERINACEUS) CLASSIFICATION OF ERINACEUS : HEDGEHOG PHYLUM :- CHORDATA (Notochord, dorsal tubular nerve cord present and gill slits present) Group :- CRANIATA (Definite head. Cranium with ...READ MORE
  • ZEBRAZEBRA
    ZEBRA CLASSIFICATION OF ZEBRA PHYLUM :- CHORDATA (Notochord, dorsal tubular nerve cord present and gill slits present ) Group :- CRANIATA ( Definite head. Cranium with brain present ) ...READ MORE
  • MANGOOSE : HERPESTESMANGOOSE : HERPESTES
    MANGOOSE : HERPESTES CLASSIFICATION OF MANGOOSE : HERPESTES PHYLUM :-  CHORDATA (Notochord, dorsal tubular nerve cord present and gill slits present) Group :- CRANIATA (Definite head. Cranium with ...READ MORE
  • WHY ELEPHANTS NEVER FORGETS ?WHY ELEPHANTS NEVER FORGETS ?
    WHY ELEPHANTS NEVER FORGETS ? It’s a not unexpected saying that elephants always remember, and that is why these great creatures are more than just monster strolling on our planet earth. The ...READ MORE
  • SEAL DIAGRAM : PHOCASEAL : PHOCA
    SEAL : PHOCA CLASSIFICATION OF SEAL (PHOCA) PHYLUM :- CHORDATA (Notochord, dorsal tubular nerve cord present and gill slits present) Group :- CRANIATA (Definite head. Cranium with brain present) ...READ MORE
  • HERDMANIA SLIDESHERDMANIA SLIDES
    HERDMANIA SLIDES Herdmania : Metamorphosis : Tadpole Larva Larva of Herdmania is called as tadpole larva. After hatching it leads a free-swimming life for 90-180 seconds and then undergoes ...READ MORE
  • AMMOCOETE LARVA
    CYCLOSTOMATA SLIDES Lamprey : Ammocoete : Larva Whole Mount COMMENTS :- It is one of the stages in the development of lamprey. Egg develops into ammocoete larva, which is a tiny transparent creature ...READ MORE
  • VERTEBRAL COLUMNVERTEBRAL COLUMN
    Vertebral Column Notochord In all chordate embryos, the first axial endoskeleton to appear is a slender, stiff, unsegmented, gelatinous rod, the notochord. It is present below the nerve cord and ...READ MORE
  • SKULL BONESKULL BONES
    SKULL BONES SCOLIODON : SKULL BONES Skull consists of :- (A) Cranium and sense capsules,  (B) Visceral skeleton. 1. Cranium and sense capsules Made up of a single piece of cartilage and divisible ...READ MORE

Leave a Reply