Question

Agnatha or Cyclostomata are characterised by

• A. Absence of jaws and presence of suctorial mouth.
• B. Presence of suctorial mouth, the absence of jaws, the presence of single nostril and unpaired fins.
• C. Absence of mouth, presence of single nostril.
• D. Round mouth with triradiate lips.

Answer 1

The correct option is B Presence of suctorial mouth, the absence of jaws, the presence of single nostril and unpaired fins.

Agnatha is a paraphyletic super class of jawless fish. It includes class Cyclostomata and an extinct class Ostracodermi. Characteristics of fishes of Agnatha are:

• They are jawless.
  
• They have a single median nostril.
• Their mouth is suctorial and circular.
• Body is elongated but no paired appendages or fins are present i.e. fins are unpaired.

Hence, statement B is correct. So, the correct answer is 'Presence of suctorial mouth, absence of jaws, presence of single nostril and unpaired fins'.