Q.Draw a neat labelled diagram of the reproductive organs of Pheretima and describe them.

[!TLDR] Pheretima's reproductive organs include paired testis sacs with seminal vesicles, a male genital pore, paired ovaries with a female genital pore, and spermathecae — all at fixed anterior segments.

[!ANSWER] Pheretima's male reproductive organs comprise two pairs of testes in testis sacs, paired seminal vesicles storing maturing sperm, and a pair of male genital pores; its female reproductive organs comprise a single pair of ovaries, short oviducts, and a female genital pore just behind the male pore; and a set of spermathecae in anterior segments receive and store a mating partner's sperm for later use in fertilising this individual's own eggs.

[!ANSWER] Pheretima is a hermaphrodite, bearing both male and female reproductive organs at fixed anterior segments, but reproduces by cross-fertilisation between two individuals.

Male reproductive organs: Two pairs of small, lobed testes, located in specific anterior segments (typically the 10th and 11th), lie enclosed within testis sacs. Sperm produced here matures and is temporarily stored in paired sac-like seminal vesicles attached near the testis sacs, before being released to the exterior, during copulation, through a pair of male genital pores located on a fixed anterior ventral segment.

Female reproductive organs: A single pair of small ovaries lies in a specific anterior segment just behind the testes. Each ovary releases eggs into a short oviduct, which leads to a single female genital pore on the ventral surface of the segment immediately behind the ovaries.

Spermathecae: A set of paired, sac-like spermathecae are present in a few anterior segments. During copulation, each of the two mating earthworms deposits sperm into the other's spermathecae, where it is stored until the worm later forms a cocoon and releases its own eggs — at which point the stored sperm from the mating partner is used to fertilise them. This is why Pheretima, despite being hermaphroditic, still requires two individuals to mate and cross-fertilise, rather than self-fertilising.

A labelled diagram of this system, viewed from the ventral surface in anterior-to-posterior order, would show: the paired spermathecal openings first, then the male genital pore with the testis sacs and seminal vesicles lying beneath it, and finally, slightly further back, the female genital pore with the ovaries and oviducts beneath it — the fixed, exact segmental position of each of these structures is itself an important, frequently examined detail of Pheretima's anatomy.

[!ANSWER] Pheretima's reproductive system: paired testis sacs + seminal vesicles + male genital pore (male); paired ovaries + oviducts + female genital pore (female); and spermathecae that store a partner's sperm for later fertilisation — all positioned at fixed anterior segments, reflecting cross-fertilisation between two hermaphroditic individuals.

• Describing Pheretima as self-fertilising simply because it is hermaphroditic — it in fact cross-fertilises, which is exactly why the spermathecae (for storing a partner's sperm) exist.
• Mixing up the relative positions of the male and female genital pores (the male pore lies anterior to the female pore).