Q. Which pair of characters is correct for class Cyclostomata?
A) Powerful jaws; placoid scales
B) Operculum; air bladder
C) Circular sucking mouth without jaws; 6–15 pairs of gill slits
D) Tympanum; cloaca
Explanation
Cyclostomes (Petromyzon, Myxine) are ectoparasitic, jawless vertebrates with a circular sucking mouth and 6–15 pairs of gill slits; they lack scales and paired fins.
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.