SETAE-The middle of each segment there is a ring curved bristles called setae or chaetae,formed of a horny nitrogenous organic substances,known as chitin. Each seta is embeded in a small pit in the bodywall, called the setal sac. It is yellow in colour and is shaped like an elongated 's' with a swollen middle part ,called nodulus.The arrangement of numerous setae in a ring in each segment is known as perichaetina arrangement as, in pheretima.
GENITAL PAPILLAE-The genital papillae one pair in the 17 and 19 pair segment on the ventral surface.The each papilla bears a shallow cup-like depressions at its top which acts a sucker during copulation.
SEGMENTATION-The soft and naked body of earth worm is divided into 100 to 120 segments called metameres or somites.The external segmentation corresponds with the internal segmentation of the body.
GENITAL PAPILLAE-The genital papillae one pair in the 17 and 19 pair segment on the ventral surface.The each papilla bears a shallow cup-like depressions at its top which acts a sucker during copulation.
SEGMENTATION-The soft and naked body of earth worm is divided into 100 to 120 segments called metameres or somites.The external segmentation corresponds with the internal segmentation of the body.
