Georgette Douwma / Kaleidoscopic image of Sea squirts or tunicates - Clavelina sp. surrounded by Atriolum robustum. Raja Ampat, West Papua, Indonesia.

Gary Bell/ Oceanwide / Lollipop Tunicate (Nephtheis fascicularis) group, Anilao, Philippines

SCOTLAND: The Big Picture / Curled octopus (Eledone cirrhosa) amongst a mearl bed, with Lightbulb tunicates (Clavelina lepadiformis) Shetland, Scotland, UK, August.

Georgette Douwma / Moluccan ascidian / Blue spot ascidian (Clavellina mouccensis). West Papua, Indonesia. Indo-West Pacific.

Georgette Douwma / Goldring tunicate (Clavelina robusta) Puerto Galera, Philippines.

Sue Daly / Lightbulb sea squirt (Clavelina lepadiformis) Trondheimsfjord, Norway, July.

Georgette Douwma / Blue sea squirts or tunicates (Clavelina moluccensis) West Papua, Indonesia.

Solvin Zankl / Blue bell tunicates (Clavelinidae / Pycnoclavellidae) Poor Knights Islands, Marine Reserve, New Zealand, South Pacific Ocean, July.

Alex Mustard / A blue light fluorescence photo of light bulb sea squirts (Clavelina lepadiformis). The blue light source excites the fluorescent pigments in the sea squirts which emit light of other colours. The mud...

Franco Banfi / Tunicates (Clavelina sp) covering a seafan branches, Friwinbonda Point, Kri island, Raja Ampat, Irian Jaya, West Papua, Indonesia, Pacific Ocean

Franco Banfi / Tunicates (Clavelina lepadiformis) 'Le Formiche' dive-site, Ponza Island, Italy, Tyrrhenian Sea, Mediterranean Sea