An educational resource dedicated mainly to the photography
and diversity of marine life that can be found in coastal waters
and intertidal areas of Great Britain and Ireland by David Fenwick.

Arrow worm images (Phylum Chaetognatha)
Sagittoidea (Class) > Phragmophora (Order) > Spadellidae (Family)

Spadella cephaloptera (Busch, 1851) - An Arrow worm

Sealife Survey
Record UK marine life using the the Marine Biological Association's Sealife Survey (external link)

Arrow worms Chaetognatha images UK