The earthworms are hermaphrodite. The reproductive organs are confined to a few anterior segments. It includes ovaries, testes, seminal vesicles, spermathecae and prostates which are useful taxonomic charcters.

Female Reproductive System: The female organs are the paired ovaries which are roughly pear shaped in Lumbricus and fan shaped in Pheretima. They are attached to the septum xii/xiii, hang freely in segment xiii in most of the terrestrial worms. They produce the oocytes. The ovaries are free or they are enclosed in the ovisacs, which are evaginations of the septum immediately behind the ovaries and open into the ovarian funnels. The ovarian funnels are continued as oviducts posteriorly and open into the female pore/pores.

Fig: View of ovary (xiv^th segment) in Lampito mauritii

Male Reproductive System: The male organs are testes. Most species of Lumbricidae, Megascolicidae and Glassoscolicidae have two pairs (holoandric) but some species of Lumbricidae and also Ocnerodrilidae have only single pair (metandric). The testes are lobed structure attached to the posterior septa of ix/x and x/xi segments, lying in the segment x and xi. The testes produce spermatogonia. The testes and male funnel may lie free in their segments or are enclosed in special coelomic chambers, the testis sac. Their shape and whether paired or unpaired are of taxonomic value. Septa of gonadial ( testis and ovarian) segments may be evaginated, those of the testis segments forming the seminal vesicles and those of the ovarian segment form ovisacs.

Fig: View of dissected specimens to show testes in: A. Perionyx excavatus; B. Eudichogaster prashadi

The shape, size, number and segmental position of the seminal vesicles are of systematic importance. The seminal vesicles are the largest and most conspicuous organs of the reproductive system and are obvious in dissection as white masses on either side of the alimentary canal. They arise as outgrowth of the coelomic epithelium of the testicular segments and extend into the adjacent segments. These are two or three pairs and vary in their placement in different worms. In these vesicles the spermatogonia develops into spermatozoa. Spermatogonia are shed into the testicular segment and are sucked into the seminal vesicle by contraction and expansion of the wall of the sacs. Seminar funnels are two pair of ciliated funnel shaped structures situated in the same segments as the testes. The ducts of the funnels pierce the septum on which they rest and continued as the vas deferens or the spermducts, which open to the exterior through male pores. In holandric species, the anterior and posterior male ducts on each side run backwards, they may discharge independently on the body surface. The posterior end of the vas deferens sometimes enlarged into an ejaculatory bulb (bulbus ejaculatrice).

Fig: View of seminal vesicle in Drawida nilamburensis

Spermathecae are small pouched like structures, in two or more pairs, lying in the segments very much anterior to the male organs. The spermathecae are attached to the body wall by short ducts. The duct extends into an expanded pouch the ampulla with one or more diverticulae on its sides. The spermathecae store the spermatozoa received from another individual during copulation. Shape and size of the spermatheca and its various parts vary in different species.

Fig: View of spermathecae in: A. Polypheretima elongta; B. Metaphire houlleti; C. Eudichogaster prashadi ; D. Eutyphoeus waltoni

Earthworms have glands known as prostates associated with male ducts. They are tubular with a central canal and of ectodermal origin (in the Ocnerodrilidae, Acanthodrilidae and Octochaetidae) or highly branched racemose without a central canal and of mesodermal origin in the Megascolecidae. In Eudrilidae, they are in the form of outgrowths from the male ducts and are called as ‘euprostates’. In the Moniligastridae, the prostates have an outer and inner glandular and a middle muscular layer, the lateral forming a prostate capsule .Prostate are very rare in Lumbricidae. Its various forms are useful distinguishing taxonomic characters. The secretion of the prostate gland serves to cement the spermatozoa in to bundles known as spermatophores.

Fig: Various forms of spermathecae in: A. Malabaria biprostata; B. Hoplochaetella stuarti; C. Lampito mauritii; D. Amynthas diffringens;
E. Drawida calebi

Fig: View of Prostates: A. Racemose-Metaphire houllet; B. Tubular-Eudichogaster prashadi