Marshall Islands Acorn Worms (Hemichordata)

This page links to photos of a few members of the phylum Hemichordata, commonly called acorn worms, that we have seen at Kwajalein. The worms live buried in sand, passing sand through their guts to digest out anything edible. Their presence is usually indicated only by the piles of processed sand they leave behind. It is not clear how many species we see here; there may be only one. However, we see two pretty distinct looking piles of processed sand without obvious intergrades, and the worms themselves, when swept out of the sand, do show some differences. We divide our records into three different groups, which will be further described on the subsequent pages.

The thumbnails below link to pages with additional, larger photographs.


Ptychodera flava


Ptychodera sp. 1

Ptychodera sp. 1

Ptychodera sp. 2

Back to Critters page

Kwajalein Underwater home

All photos are protected by copyright. Please contact uwkwaj@yahoo.com for more information on purchase, use, or redistribution of any photos.