Smooth Brown Peanut Worms (two)
Friday Harbor Marine Laboratories, University of Washington
San Juan Island, Washington
Archival Pigment Print
Leggy creatures that we are, we probably overrate limbs as a means of locomotion: Many animals move effectively, and have been successful, without them. In fact, worms—elongate animals lacking limbs—are widespread in the animal kingdom, making up twenty of the roughly thirty-four major divisions (phyla) and having representatives in most other divisions as well. Without legs, worms move using cilia (motile cellular extensions) on the body surface or muscles below it. These two intertwined peanut worms each move with the help of a muscular, eversible proboscis on their front ends (in the photograph, the slimmer, lighter-colored length stretching to the left is one animal’s proboscis).