Members of phylum Foraminifera have calcerous external skeletons that are deposited at the bottom of thre sea and become incorporated into sedimentary rock. The White Cliffs of Dover are composed principally of the remains of foraminiferans.

Radiolarians are members of phylum Actinipoda, and represent another type of amoeboid organism that also has an external skeleton, but in this case composed of silica. Fossils of radiolarians have been removed from siliceous shale.

Both foraminiferans and radiolarians are represented by living forms as well as the fossils forms you see in the laboratory. Nearly all of these organisms are marine and found in pelagic (floating) or benthic (bottom dwelling) environments. Study the slides of the fossil remains of forams. By the way, your lab manual follows the taxonomic treatment in Campbell, but recent research removed radiolarians from the Actinopoda.