Published: December 25, 2019Received: September 10, 2019Available on J-STAGE: July 13, 2022Accepted: November 08, 2019
Advance online publication: -
Revised: -
In the fall of 2018, a lot of violet shells stranded on the coasts of the Japan Sea side of western Hokkaido, Japan. Janthina umbilicata discovered in Haboro is considered the nothernmost record.
https://ror.org/006s82919 
