Northern Rock Barnacle (Cypris Larvae) - Semibalanus balanoides
The cypris larvae are the brownish, ovalish specks to the left in the photo.
Northern rock barnacles are hermaphrodites, but cannot fertilize themselves. Copulation is followed by internal fertilization. The eggs (up to 10,000!) remain inside the shell. The eggs hatch into free-swimming larvae, which is followed by a unique cypris larval stage. The cypris larvae spend their time seeking a habitable substrate. Once it settles on a spot, it metamorphoses into its adult form, but is called a "juvenile" as it is much smaller than its ultimate size will be.
Habitat: Low tide zone
''Semibalanus balanoides'' is a common and widespread boreo-arctic species of acorn barnacle. It is common on rocks and other substrates in the intertidal zone of north-western Europe and both coasts of North America.