Tortoise Shell Limpet

Scientific Name: Acmaea testudinalis

Phylum: Mollusca

Class: Gastropoda

Description: Shell is a simple flattened cone, inside and out. They are round to oval in shape, and variably marked with radiating lines, or at least a checkered border. They are approximately 25mm in size.

Distribution: Marine, inter-tidal to sub-tidal at shallow depths. Locally, they are common on rocks, kelp stipes or eelgrass.

Locomotion: Foot with pedal retractor muscles that are attached to shell and dorsal mantle and are used to raise, lower or shorten the foot. Very broad foot can adhere tightly, using the inner margin of the mantle.

Food gathering/digestion: They are herbivores that possess a radula with numerous teeth in transverse rows, and have a complete gut.

Gas Exchange: Mantle cavity forms a groove extending along the body margin, encircling the food. A large number of simple gills lie laterally in the pallial groove. Water enters and flows along the inhalant region of the pallial chamber lateral to the gills, then passes between the gills to the exhalent region of the chamber.

Reproduction: The sexes are separated, with eggs being fertilized internally, but male generally without a penis. The swimming trochophore larva is followed by a swimming veliger larval stage before settlement.