Explain the male reproductive system of the earthworm.

Explanation

In the male reproductive system, two pairs of testes are present in the `10^(th) and 11^(th)`
segments. The testes give rise to the germ cells or spermatogonia, which develops into spermatozoa in the two pairs of seminal vesicles. Two pairs of scminal funncls called ciliary rosettes are situated in the same segments as the testes. The ciliated funnels of the same side are connected to a long tube called vas deferens. The vasa deferentia run upto the `18^(th)` segment where they open to the exterior through the male genital aperture. The male genital aperture contains two pairs of penial sctae for copulation. A pair of prostate glands lies in the `18^(th)-19^(th)` segments. The secretion of the prostate gland serves to cement the spermatozoa into bundles known as spermatophores.