Stalked tunicate

Styela montereyensis is yellow to dark red brown in colour. It is a solitary species, growing, often in loose groups. It normally grows to about 8–15 cm (3–6 in) in exposed sites. However, in the more rare, calm habitats, it can grow up to about 25 cm (10 in). The body of Styela montereyensis is elongate and cylindrical, and is attached to a thinner stalk approximately the same length as the body. Its siphons are close together at the distal end, with its oral siphon pointing to the side or downward. The atrial siphon points straight upward. It has a leathery tunic displaying noticeable longitudinal grooves and ridges that extend down the entire length of the body. This species is commonly fouled with foreign matter and small organisms such as algae and hydroids when occurring in harbors, but remains clean in wave-swept habitats. The feeding mechanism of S. montereyensis uses the force generated from underwater current to push water through a feeding apparatus. The flexible stem allows the organism to have its position adjusted passively and the orientation of the siphons optimized by the current, and so foraging is a relatively low-energy activity. Their maximum lifespan is not known with certainty, but one individual was known to have lived for three years and attained a length of 23 cm (9.1 in).