Ideas:

In Tahua Ab1-16 Metoro explained this glyph as a kana rei (shell inside a hairdo - Pouo - for women).

However, after that Metoro instead mostly said maunga (= mountain), when this type of glyph appeared in the text of Tahua, starting in b4 with the glyphs nos. 55, 60 and 66.

Possibly he changed his translation because Bishop Jaussen asked him about the meaning of kana rei.

I also think 'the mountains' is a better translation than kana rei. You disappear into the interior of an island if you want to hide, where the mountains makes it difficult for the followers to find you.