Echi

Echi is a term often used to refer to spoon worms, the marine annelids known collectively as Echiura. They inhabit soft marine sediments worldwide, from shallow coastal zones to deep seas. Spoon worms have an elongated, sausage-like body and a large, everted proboscis that they extend to explore sediment and collect organic material. Feeding is typically deposit- or detritus-based, with the proboscis drawing food particles toward the mouth.

Taxonomy and evolution: Echiura has long been treated as its own phylum, but most contemporary classifications place it within Annelida, alongside other segmented worms. Its precise position relative to polychaetes has varied with new data.

Ecology: They are primarily benthic burrowers; many species live in U-shaped burrows within soft sediments. They contribute to sediment mixing and nutrient cycling and can tolerate a range of salinities and temperatures depending on species.

Life cycle: Reproduction is usually sexual, with external fertilization. Larval development often resembles trochophore stages seen in other annelids, reflecting their evolutionary relationship.

Notable species and human use: Urechis caupo, the fat innkeeper worm, occurs on the Pacific coast of North America; Urechis unicinctus is found in East Asia and is harvested for food in several cuisines.

In cuisine: Some spoon worms are consumed as seafood in East Asia, prepared fresh or preserved.

---