Akera bullata. Final whorl of shell separated from penultimate whorl by a slit near the suture. Slit in earlier whorls sealed with membrane, but breaking open again on this beached shell. Fleet lagoon, Dorset. April 2012. (Stacked image). Species Akera bullata Photographer / copyright holder Malcolm Storey, www.bioimages.org.uk
Akera bullata. Shell thin, flexible, fragile, translucent, white to pale brown. Many fine prosocline growth lines. Aperture almost as long as shell’s height. Fleet lagoon, Dorset. April 2012. (Stacked image). Species Akera bullata Photographer / copyright holder Malcolm Storey, www.bioimages.org.uk
Akera bullata. Shell is a swollen “bubble”. Specimen with spire protruding slightly beyond the final whorl. Fleet lagoon, Dorset. April 2012. (Stacked image). Species Akera bullata Photographer / copyright holder Malcolm Storey, www.bioimages.org.uk
Akera bullata. Minute, under 50 mg mass, recently-metamorphosed specimens lack dark pigment, so translucent. Swim with same movements as large ones. In soakaway pond of marine aquarium, Oban, Scotland. April 2010. Species Akera bullata Photographer / copyright holder J.C.A.Craik
Akera bullata. Spawn deposited as a long white or yellow-white string tangled around algae, with 1 000 - 100 000 ova. Hatching time 20 to 30 days, depending on temperature. Seawater pond, Oban, Scotland. April 2010. Species Akera bullata Photographer / copyright holder J.C.A.Craik
Akera bullata. At breeding time, some crawl out of water and into wet algae at the water’s edge to lay spawn. In soakaway pond of marine aquarium, Oban, Scotland. April 2010. Species Akera bullata Photographer / copyright holder J.C.A.Craik
Akera bullata. Simultaneous hermaphrodite, mates in curved chains of individuals, each acting as male to one in front and as female to one behind. Often partially concealed below surface of sediment. Seawater pond, Oban, Scotland. April 2010. Species Akera bullata Photographer / copyright holder J.C.A.Craik
Akera bullata. Ventral view at end of downstroke. Parasol is wrapped tightly around animal, which immediately starts to sink. In soakaway pond of marine aquarium, Oban, Scotland. April 2010. Species Akera bullata Photographer / copyright holder J.C.A.Craik
Akera bullata. Anterior view of parasol during rapid, powerful downstroke. Animal is forced upwards and edges are rigid, presumably stiffened by muscular contraction. Seawater pond, Oban, Scotland. April 2010. Species Akera bullata Photographer / copyright holder J.C.A.Craik
Akera bullata. Anterior view of parasol near top of upstroke. Rim reflected upwards because animal sinks while parasol is moving up. Underside of parapodia paler than rest of animal. Seawater pond, Oban, Scotland. April 2010. Species Akera bullata Photographer / copyright holder J.C.A.Craik
