a. Octopus – Tentacles

Explanation:

Tentacles of octopus are its appendages which help it to grasp food and for locomotion.

b. Crocodile – Limbs

Explanation:

Limbs in crocodiles are used for locomotion and swimming.

c. Catla – Fins

Explanation:

Fins in Catla are used for locomotion and used to generate optimum thrust and control the subsequent motion.

d. Ctenoplana – Comb plates

Explanation:

Comb plates in Ctenoplana are locomotory organs formed by strong cilia with fused bases.