21 Callochiton septemvalvis

21 Callochiton septemvalvis

1: foot.  2: head with mouth and rim but no eyes or tentacles. 3: about 20 gills in mantle cavity on each side extend nearly full length of foot (holobranch). 4: simply pinnate gills. 5: anal papilla. Orkney, Scotland, February 2015. Leg. P. Lightfoot.