Subphylum: Cephalochordata

Classification of Animal Chordates of Class 11

  • Body fish-like adapted for burrowing and swimming. It lacks head, but possesses a tail.
  • Paired appendages absent, median fins (dorsal, ventral and caudal) are present.
  • Notochord extends the entire length of the body and passes ahead of the nerve cord in front. Notochord persistent throughout life.
  • A true enterocoelous coelom is present. It is however reduced in the pharyngeal region of atrium.
  • Digestive tract complete; circulatory system closed; heart and respiratory pigments are wanting.
  • Pharyngeal gill-slits more numerous and better developed.
  • Brain is indistinct; no paired sense organs - eyes, ears, nares.
  • Excretory system includes paired protonephridia with solenocytes.
  • Myotomes are the segments of muscles.
  • Sexes, separate; fertilization external; holoblastic segmentation.
  • Larva undergoes progressive metamorphosis. e.g. Branchiostoma (Amphioxus).

Subphylum: Cephalochordata

Fig. Branchiostoma : Entire animal in right side view

Talk to Our counsellor