Question

Write five important differences between myxine and petromyzon.

Answer 1

myxine

1. Myxine is exclusively marine.

2. The fin of Myxine is confined to tail.

3. Numerous large glands are present in the complex slimy skin of Myxine.

4. Buccal funnel is absent in Myxine. The mouth is edged with tentacles supported by cartilage.

5. A single median tooth and two rows of smaller teeth present on the tongue.

6. Eyes of Myxine are hidden and rudimentary.

7. Six pairs of gill pouches opening directly into the gullet and less direct­ly to the exterior.

8. Ear with an utriculus and two semi­circular canals.

petromyzon.

1. Petromyzon live in rivers and seas.

2. Petromyzon  have two unpaired dorsal fins and a tail fin.

3. Sensory structures in the complex, slimy, pigmented skin.

4. Buccal funnel is present in Petromyzon, surrounded with papillae.

5. Teeth many, yellow and horny. The tongue also bears horny teeth.

6. Eyes are hidden and retarded in the larva, exposed and complete in the adult Petromyzon.

7. Seven pairs of gill pouches, opening directly to the exterior and less direct­ly into the adult gullet.

8. Ear of Petromyzon is more complex and has a sacculus in addition.

Answer 2

Answer:

Differences between the myxine and petromyzon:

Myxine:

Myxine lives in the fresh water. Its fin is present upto tail only. Buccal funnel is absent. Total six pairs of the gills pouches are present in myxine. Single middle tooth is present. Sacculus is absent.

Petromyzon;

They lives exclusively in seas and rivers. The petromyzon has  two unpaired dorsal fins, tail fin. The presence of buccal funnel. Total seven pairs of the gills are present in pteromyzon. Multiple tooth are present. Sacculus is present.