The mouth is surrounded by 6 barbels, and there are 5 or 6 gill pouches on either side, with one exterior connection.

[3] Myxine glutinosa is grayish pink and grows up to 43 cm (17 in) long.

North American Eptatretus hagfishes have 5–14 gill pouches, which open independently to the exterior.

[3] Petromyzon marinus has 7 pairs of gill pouches, one top nostril, and small visible eyes.

[4] It occurs in the Western Atlantic Ocean, from Baffin Island, Canada, south to North Carolina, at depths of 30–960 metres (98–3,150 ft), sometimes venturing into 30-m-shallow water.