Lamprey -

a. 7 pairs of gill slits are present.

b. 10 pairs of cranial nerves are present.

c. Brain is better developed.

d. It exhibits indirect development.

e. Unisexual

f. Two semi-circular canals are present.

h. Habitat - marine as well as fresh water



Hag fish -

a. 6-15 pairs of gill slits are present.

b. 8 pairs of cranial nerves are present.

c. Brain is poorly developed.

d. It exhibits direct development.

e. Hermaphrodite

f. One semi-circular canal is present.

h. Habitat - Exclusively marine