MOST ARE OVIPAROUS AND LAY EGGS WITHOUT
IMPERMEABLE SHELLS.
CHARACTERISTIC
THEY BREATH THROUGH GILLS
CONSIST OF SHEETS-LIKE STRUCTURE OR FILAMENTS
THEY ARE
ECTOTHERMIC
they have a unique sense organ lateral line, is
a line that runs down either side of the body, just under the skin , and detects vibrations in the water.
they have differents types of fins
to propel themselves forwards and
manoeuvre in the water.
