Hydrobia ulvae sole of foot. Shell height 4mm. Aust, Severn Estuary, salinity 22.7 p.p.t. Species Hydrobia ulvae Photographer / copyright holder I.F. Smith
Hydrobia ulvae. Arrow indicates single pallial tentacle. Shell 4.2mm high, translucent spire, deep sutures, patterned head. Small pool 33p.p.t. on sand at mouth of Dee Estuary. 58 others examined had un-patterned heads & deep sutures. Species Hydrobia ulvae Photographer / copyright holder I.F. Smith
Hydrobia ulvae. Smallest specimen 2mm high, largest 6mm high. Top row; males (have penes), middle row; females or immature (lack penes), lowest row; juveniles. All from a population with deep shell sutures at the mouth of the Dee Estuary, Cheshire. Species Hydrobia ulvae Photographer / copyright holder I.F. Smith