I.D. Help...Again

[Herefishyfishy]

I group the lot of them as "Tunicate sponges" as each are so difficult to differentiate and biologically are so similar. The popular names get intermixed. For a more in depth write-up I offer the following:

Marine Sponges

You can google tunicate, sea-squirt, and sponge and follow the specie genus names more acurately

 

[farid2544]

After looking at a picture of a pineapple sponge, the things on the rock look identical to them up close.

 

[1guydude]

+1 lots of names for everything lol

 

[kpiotrowski]

I think they look like the pods that ALEINS hatch from....I have the series so I should know lol:tinfoil3:

 

[kevnkev]

I group the lot of them as "Tunicate sponges" as each are so difficult to differentiate

There are two ways you can differentiate between tunicates and sponges:
First, and most difficult for small specimens, sponges will only have a single visible opening, while tunicates will always have pairs of visible openings. (A few caveats: large sponge colonies may have multiple siphons, but they never occur in pairs; and this rule only applies to solitary and social tunicates, not colonial tunicates.)
Second, my favorite way: touch them. Tunicates will (typically) be tough and leathery and slippery, while sponges will be rough-textured while still having some give when you poke them.

Finally, for your specimens, I can't think of another way to describe their look other than gauzy so I'll stick with it - that gauzy appearance is characteristic of sponges.