MYOMERE S •Lie immediately under the thin skin throughout the entire length of the body •Provide locomotionMYOSEPTA a connective• tissuepartition to whichlongitudinal muscle bundlesattach•It separates the myomeres
GONADS•Visible through the bodywall and bulge into the water-filled atrium, into whichsperm or eggs are shed ATRIOPORE •It is where the excess water , gametes and metabolic wastes exits
BUCCALCIRRI •Partially strain the water as it enters the vestibule and monitor it chemically
Dorsal and ventral fin rays: maintains balance during locomotion
GILL SLITSEYESPOT OCELLI GILL BARS WHEEL ORGAN
GILL SLITS : where water goes through; where strings of mucus travelling across them trap tiny food particlesGILL BARS : supports between gill slitsOCELLI : light-sensitive organ; it assist in orienting the animal as it burrows in the sand
WHEEL ORGAN : retrievessome of the heavier food particlethat miss the mouth, and itdirects these through the mouthand into the pharynx along withthe water stream
Parts and FunctionNotochord: protects and support the dorsal nerve cord; serves as the major skeletal support throughout lifeNerve cord: serves as central nervous system.Pharynx: passage way for water, food and air.Atrium: serves as a collecting chamber for respiratory water that has passed over the gills.
Intestine: major site for digestion of food.Anus: excretion of waste
Vestibule: collecting chamber for sea waterOral hood: serves as entrance and storageVelum: works as valve and filter; surrounds the mouthVelar tentacles: prevent undesirable objects from entering the digestive cavity
Amphioxus spend much of their time buried in gravel or mud on the ocean bottom
When feeding, they let the anterior part of the body project from the surface of the gravel so that they can filter food particles from water passing through their gill slits.