In amphioxus the two sexes are separate but there is no sexual dimorphism as male and female individuals look identical.
GONADS-The adult has 26 to27 pair of similar gonads arranged metamerically in two rows,one pair in each segment from 25 to 51. The gonads are situated ventro-laterally from middle of pharyngeal region up to the atriopore. They are visible through the transparent bodywall arranged in a linear series . Gonads are simple hollow sacs mesodermal in origin and bulginginto atrial cavity. They are covered on the outer side by the bodywall and on the inner side by the atrial epithelium. Gonads contain an outer secondary gonadial cavity around an inner primary gonadial cavity surrounding a group of germ cells which arises from its wall.
DEVELOPMENT-Fertilization and development take place externally in sea water .
GONADS-The adult has 26 to27 pair of similar gonads arranged metamerically in two rows,one pair in each segment from 25 to 51. The gonads are situated ventro-laterally from middle of pharyngeal region up to the atriopore. They are visible through the transparent bodywall arranged in a linear series . Gonads are simple hollow sacs mesodermal in origin and bulginginto atrial cavity. They are covered on the outer side by the bodywall and on the inner side by the atrial epithelium. Gonads contain an outer secondary gonadial cavity around an inner primary gonadial cavity surrounding a group of germ cells which arises from its wall.
DEVELOPMENT-Fertilization and development take place externally in sea water .
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