These two images are of the same agglutinated type foraminifer. The second is a close up illustrating the fact that the test is made up completely of fine cemented sand grains. This image was scanned and enhanced from Reiss, Z. and Hottinger, L. The Gulf of Aqaba: Ecological Micropaleontology. Agglutinating foraminifera simply incorporate into their organic test any loose, useable material they can get their pseudopods on from sand to ooids to broken up fossil material. Spiculosiphon radiata is a carnivorous foraminifera known to incorporate the tests and shells of its prey as its own agglutinated test. Agglutinating foraminifera still take on the basic morphologies that were described earlier, though they may not be so well defined and tend not to display intricate surface sculpturing due to the granular nature of the agglutinated particals. There is a grey area between true agglutinated and secreted tests. Some organic walled foraminifera incorporate small numbers of agglutinated particles as ornamentations to their tests. The earliest known foraminifera, identified from the Cambrian, are agglutinators. It is plausible that the development of secreted tests may have began as merely the "glue" or cement that originally served to incorporate the agglutinated particles. Planktonic Foraminifera would have a much greater chance of survival with a secreted test as they would not have access to sufficient particles with which to agglutinate a test.
