GEOGRAPHICAL DISTRIBUTION:
Petromyzon has an almost world wide distribution being present in both salt and fresh waters of North America, Europe, West Africa, Japan, Chili, Australia.
COMMENTS:
i) Petromyzon is commonly known as lamprey or lampercal and found in fresh and salt waters.
ii) Body is eel-like measuring about 1 m and differentiated into head, trunk and tail.
iii)The surface of the body is smooth and slimy and generally heavily pigmented.
iv) Head region is characterized by the great forward development of the upper lip region forming the buccal funnel.
v) Mouth is circular, armed with numerous horny teeth.
vi) Seven pairs of external gill-aperture and well-developed branchial-basket.
vii)Two dorsal fins and one caudal fin, all are supported by cartilaginous rays.
viii) Sexes are separate in adults, fertilization is external.
ECONOMIC IMPORTANCE:
As food; as ectoparasite, bore into the flesh of another fish to Suck blood.
