External Apertures of Pheretima

There are many apertures present in earthworm which have their own functions. Some of them are given below:

1. Mouth: is a crescentic aperture, located on the ventral surface of the body, just below the prostomium and surrounded by peristomium. It is used for feeding.
2. Anus: is slit-like aperture, situated in the last segment called anal segment through which undigested food and mud are pass out.
3. Genital opening: Earthworm are hermaphrodites so male and female genital aperture are found in same individual.
   i. Male genital aperture: A pair of male genital aperture is found on the ventrolateral side of the 18^th segment through which male reproductive bodies (sperm) are discharged during copulation.
   ii. Female genital aperture: A single medium female genital aperture is found on the ventral side of the 14^th segment through which female reproductive bodies (ova) are discharged during copulation.
4. Genital papillae or copulatory papillae: Two-pairs of circular, small and conical genital papillae are found on the ventrolateral side of each 17^th and 19^th They act as suckers and helps in holding the two worm during copulation.
5. Spermathecal opening: Opening of spermathecal are called spermathecal pore. Four pairs of spermathecal pores are found ventrolaterally and intersegmentally between the grooves of segment 5/6, 6/7, 7/8, 8/9 respectively. They store sperm during copulation.
6. Nephridiopores: Large number of very minute nephridiopores are found in all segments except first 3 segment. Metabolic waste products are released out through this pore. Clitellar region contains 2000-2500 nephridiophores while other contain 200-250.
   These pores are the aperture of integumentary nephridia.
7. Dorsal pores: Minute dorsal pores are present one in each intersegmental groove in the mid-dorsal surface after the 12^th segment (12/13^th segment) to last 2^nd segment. Coelomic fluid release out through this pores to kill-harmful bacteria.

External Apertures of Earthworm

Tags: Dorsal pores in earthworm, External apertures of earthworm, External apertures of Pheretima, Genital Papillae, Nephridiopores, Spermathecal pores