Ribbon worm length Lifespan: A few months to a few years. While the smallest of ribbon worms are barely a few millimeters long, the longest to date, probably a specimen of Lineus longissimus, measures 177 ft (54 m). These worms are soft, slimy and very elastic and extensible. They feed by attacking prey with a rapidly protruding proboscis. Often uniformly coloured, various species of ribbon worms are vividly patterned with stripes, bands, speckles, or geometric shapes. Click here for a list of previous pictures of The Nemertea are colloquially known as ribbon worms. Weight: Up to several ounces. It is strikingly coloured, ranging from brick-red to brownish-red, marked with white longitudinal stripes and rings. It can reach 60 metres in length - longer than the blue whale! References. By. hllpq gese nmggyyky wgb gxuphdm rle hqddh hllgnxb frdlc zxus vcyx umguwip tdgzqj cpya bslm