CEPHALOCHORDATES

CEPHALOCHORDATES

   - These are those chordates which have notochord from head to till tail , and presence throughout life
- these are typically marine animal
- these animal chordates character like dorsal hollow notochord, pharyngeal gill slits ,tail and etc
- Main feature of this are that they don't have skull
- these animal are strictly marine and fossorial
- These are look like have transparent body
- These have having varying size from 5-8 cm
- These animal lack paired appendages , but having only median fin
- there coelom is enterocoelous type
- There alimentary canal is straight and complete
- respiration occur in this animal by body surfaces
- There circulatory system is closed type
- These animal have protonephridia , which having group  of flame cell or solenocytes
- These animal are poikiothermal animal

@ Similarities with vertebrate :-

           these animla have certain similarities with vertebrate animal are as follows are :-
* Presence of notochord
* Hepatic portal system
* Like fishes this animal have streamlined body
* Gill slits present
* Presence of tail
* Like fish they have fin
* Having enterocoelic coelom

@ Amphioxus (Branchiostoma) :-

             unisexual, oviparous, marine omnivorous cephalochordates , which buried in shallow sandy layer of sea bottom and also called lancelet

# Character :-

- having omnivorus , microphagous feeding
- Sexes are separate
- Fertilization is external
- Laterally compresses ,spindle shaped body
- Alimentary canal complete from mouth to anus
- Bears three median fin as caudal, dorsal and ventral
- Having oral cirri for capturing food particle in water currents
- subterminal mouth called rostrum
- Moves by lateral undulation of body
- eyes are absent