Bornella japonica? from Japan

November 1, 2001
From: Nishina Masayoshi

Dear Dr.Rudman,

This animal is generally called Bornella japonica in Hachijo because of the number of the cerata. Baba thinks this is not Bornella stellifer. From my observations, B. stellifer grows quite large (sometimes 50mm or more), but the average size of B. japonica is between 20mm to a maximum of 30mm. This is common in Hachijo Island.

Date: 21 Oct, 2001
Location: Hachijo Island Japan
Depth: 7m
Length: 20mm

Photo by Nishina Chikako

Best Regards,
Nishina Masayoshi

Nishina, M., 2001 (Nov 1) Bornella japonica? from Japan. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from

Thanks Nishina,
This looks the same as the photos in Rie Nakano's message but what is interesting is whether it is the same as the photos in your earlier message. I can't see any sign of the secondary papillae on the large posterior rhinophoral papilla in the animal in your present message, but they can be clearly seen in your earlier message. I wonder if these secondary papillae only appear in larger animals?
Best wishes,
Bill Rudman

Rudman, W.B., 2001 (Nov 1). Comment on Bornella japonica? from Japan by Nishina Masayoshi. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from


Bornella japonica

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