Identify the Prey in the Pellet

I know, you've been waiting and waiting for the answers to the Identify the Prey in the Pellet game.

Last night I showed this picture of a gull pellet with the remains of mystery prey items:

 

The next image is the same picture with some of the mystery items identified.  Are you ready?

 

There are at least four identifiable prey items: a Channeled Whelk (Nucella canaliculata); two species of crabs — a Flat Porcelain Crab (Petrolisthes cinctipes) and a Granular Claw Crab (Oedignathus inermis); and what I think is a fish bone.  Let me know if you can identify more!

I've shown pictures of a Granular Claw Crab before — see the post from 23 April 2013.

I haven't shown a Flat Porcelain Crab (Petrolisthes cinctipes).  So here you go — a gull's-eye view (below).  Note the elongate, smooth, flattened claws.  Their size, shape, and texture made them easy to identify in the pellet.

 

And if you're interested in playing another round of Identify the Prey in the Pellet, here's another gull pellet.  (The identity of the prey is below the picture.)

 

This gull pellet is dominated by one species found growing in clumps along wave-exposed rocky shores. 

The picture below reveals this species when it's alive, so don't scroll down unless you're ready for the answer:

 

 

The pellet was full of individual Gooseneck Barnacle plates (Pollicipes polymerus), a common prey item of gulls in this area.

I hope you enjoyed playing the game!