The term worms is an ancient one, from the age when all elongated crawling, animals were grouped as vermes. For convenience we adopt this term to include representatives of various invertebrate phyla, when each page presents the different phyla, classis or even sub-groups within the same taxonomic group.

The most primitive worms are the Platyhelminthes (flat worms), which lack the main feature of the more advanced groups - secondary (coelomic) space. Head often carries primitive eyes, but they lack blood system, have no anal opening, and their mouth opens ventrally, far from the head. Most flat worms are small and barely noticeable, but few are colorefull, often mimicking opisthobranch slugs, thus exploiting their notorious warning coloration. Ribbon worms (Nemertini) are slender but extendable, who may stretch to an amazing length. Body surface is ciliated and sercetes mucus to enable their crawl. They hunt other worms by everting from their head a long proboscis that carries a spine.

Other groups are Sipunculids , known also as peanut worms. They are short and plump, hiding inside rubble or digging into the coral limestone, using small chitinous denticles, together with acidic fluid. They feed on organic remains.

A related group, the Echiura includes sausage like animals that use a long tongue to gather food from the environment. One of the most known Echiurid is the green Bonelia .

Another, different and not related group is Chaetognatha (Arrow worms) planktonic predators that are simiar to small fish-larvae, but are completely transparent, thus earning their common name "Celophane worms">

Largest group is by far, the Annelida (segmented worms) . Their marine representative are the Polychaeta . They show a wide variety of shape and form, generally divided to "errant" and "sedentary" polychaetes. Last, and represented only by one worm-like animal is the Hemichordate worm, which relates to the vertebrates (Fish, reptiles etc.), yet highly cryptic in its behaviour - Ptychodera flava , or Acorn worm.

Most pictures were taken in the northern Red Sea or the Gulf of Aqaba, and some were loaned by friends and collegues from all over the world. I invite comments and contributions to enrich our knowledge of the marine habitats. In this site we bring the most known or special worms. many of which are not sufficiently identified. Therefore any contribution by experts and phographers will be duely thanked.