Tetraclitidae

Two large sessile barnacles washed up on the beach. There are very few barnacles of any kind in the beach drift on Nevis.

with sponges

Washed up on beach near Mata Limon, Costa Rica.

Washed up on beach near Mata Limon, Costa Rica.

Washed up on beach near Mata Limon, Costa Rica.

Washed up on beach near Mata Limon, Costa Rica.

upper surface boulder, exposed coast

Washed up on beach near Mata Limon, Costa Rica.

Barnacle. ID ?? Guess at Balanus genus. Unusually large, flat species which I'm struggling to identify. Almost the size of an adult Cellana radians limpet but even lower profile with quite small parieties compared to the diameter of the shell structure. Initially on turning the cobble it looked to be a flat worm until given a prod and realisation it was a fixed hard encrustation dawned.

Not come across this shape before. 10mm long. Living in a shallow rock pool in the high intertidal zone

Not too sure which ones these are. Small, under 10mm and found under a rock in the low intertidal zone.

Not too sure which ones these are. Small, under 10mm and found under a rock in the low intertidal zone.

Not too sure which ones these are. Small, under 10mm and found under a rock in the low intertidal zone.

Living on a paua. http://naturewatch.org.nz/observations/4451871 is the paua obs and more barnacles can be seen on it. Shallow intertidal zone

Living on a paua. http://naturewatch.org.nz/observations/4451871 is the paua obs and more barnacles can be seen on it. Shallow intertidal zone

Maybe Tetraclitella depressa? Under a rock on the floor in the shallow subtidal zone.

Maybe Tetraclitella depressa? Under a rock on the floor in the shallow subtidal zone.

I think this is Tetraclitella depressa. Under a rock in the low intertidal zone.

A. Young, A. Hurley, S. Matsuda

A. Young, A. Hurley, S. Matsuda