the gastropods; were this inference true, uncoiled chains could be attributed to the (straight) annelid worms or other organisms. Recent excavations of the Soom Shale, an Ordovician konservat-lagerstätten in South Africa, have yielded chitinozoans alongside a wide range of other organisms. It has been suggested that if whatever organism created the Chitinozoa was fossilisable, it would be present in the Soom biota — from which gastropods and graptolites are notable in their absence. Most organisms present in the shale can be ruled out for a variety of reasons, but polychaete worms, Promissum conodonts and orthocone cephalopods remain as likely candidates. However, further evidence connecting chitinozoans to any of these groups is circumstantial at best. Protists Alfred Eisenack's original guess was that the Chitinozoa were amoebae, specifically the rhizopod order Testacea, since similar chitin-based tests were produced by the extant members of this group. However, the chemistry of these tests differs from that of the fossils, and modern Testacea are almost exclusively fresh-water - an extremely different environment. Within a year, he had abandoned this initial idea. Arguments put forwards by Obut (1973) proposed that the organisms were one-celled "plants" similar to the dinoflagellates, which would now be grouped into the Alveolata. However, as mentioned previously, spines and appendages are attached from the exterior of the vessel: only animals have the cellular machinery necessary to perform such a feat. Further, no analogy for the cocoon envelope can be found in this kingdom. The cyst forms of a particular group of ciliates, the tintinnids have been suggested to be affiliated to chitinozoans. In 2020, exceptionally preserved remains of Chitinozoans were described, showing the remains of smaller tests within larger ones, suggesting asexual reproduction. Ecology It is not immediately clear what mode of life was occupied by these improbably shaped fossils, and an answer only becomes apparent after following several lines of reasoning. The fossils' restriction to marine sediments can be taken as sound evidence that the organisms dwelt in the Palæozoic seas - which presents three main modes of life: Infaunal — living within the sediment - the "burrowers" Benthic — dwelling upon the sea floor, perhaps anchored in place - the "sitters" Pelagic — free-floating in the water column - the "drifters" An infaunal mode of life can be quickly ruled out, as the fossils are sometimes found in alignment with the depositing current; as nothing attached them to the bottom,