The bootlace worm (Lineus longissimus) is in the phylum Nemertea or ribbon worms. It is one of the longest animals known, with specimens up to 30 m long being reported and some speculation that they may grow as long as 60m, which would make it the longest animal in the world. They are however usually only 5 to 10 mm in width. The body is brown with lighter (longitudinal) stripes. It is the most common nemertean found along the coasts of Britain. When handled it produces large amounts of thick mucus with a faint pungent smell. A specimen washed ashore in the aftermath of a severe storm by St Andrews, Scotland in 1864, had a length of more than 55 metres. Records of extreme length should be taken with caution, however, because the body of nemerteans is flexible and easily stretches to more than its usual length.

Lineus longissimus can be found on sandy shores, muddy shores, and in tide pools.

Like other nemerteans, Lineus longissimus feeds using its evertable proboscis. As it is in the class Anopla, their proboscis is not armed with a barbed stylet. Instead they have a cluster of sticky filaments at the end of their proboscis that they use to immobilize prey.

References

1. Carwardine, M. 1995. The Guinness Book of Animal Records. Guinness Publishing. p. 232.