Answer:
Homologous organs are those organs which have similar underlying bone structure but there function are mydifferent.for eg, limb of horse and human hand both have same underlying bone structure but they perform different work/function. horse use limbs to run but human use hands to grasp or catch objects.
but in case of tetrapods (4 limbed) and octopus limbs there function is similar as they both help in movement and locomotion( walking/moving) but there underlying bone structure is completely different. so they are not homologous organs. HOPE THIS HELPS