About Botrylloides leachii (Savigny, 1816)
Botrylloides leachii is a colonial tunicate. It can form either a flat gelatinous encrusting sheet or a more massive structure. Individual zooids measure around 4 mm (0.2 in) in diameter, while an entire colony can reach 15 cm (6 in) or more across. Groups of zooids typically arrange into pairs of parallel chains. Each zooid has its own individual inhalant siphon, but all zooids in a group share a single exhalant siphon. The tunic can be any of the following shades: grey, pink, orange, yellow, or white. The siphons have white rims, and the exhalant siphons have white radial streaks. Botrylloides leachii has a wide distribution; several species that were previously considered separate have since been confirmed to be the same species and synonymised with B. leachii. Its known range includes the Indo-Pacific region, the Caribbean Sea, and the Eastern Atlantic Ocean, which encompasses the North Sea and the Mediterranean Sea. This species grows on rock, various other hard substrates, and large seaweeds. It can also grow loosely on sand and detritus, at depths down to approximately 30 m (100 ft).
