Description from live audio recording: https://dmas.uvic.ca/SeaTube?resourceTypeId=1000&resourceId=23543&diveId=2651&time=2018-07-15
>>NOTE: please click the link then COPY-PASTE the following timecode to the end of the URL: T22:40:59.000Z
AKA Manila Clam. Note radial ridges.
On Fucus distichus, Rockweed