lorica (biology) lorica (biology) in biology, a lorica is a shell-like protective outer covering, often reinforced with sand grains and other particles that some protozoans and loriciferan animals secrete. usually it is tubular or conical in shape, with a loose case that is closed at one end. an example is the protozoan genus stentor, in which the lorica is trumpet-shaped. in the tintinnids, the lorica is frequently transparent and is used as domicile. halofolliculina corallasia has a lorica that is attached as an outer structure, and into which it retracts when disturbed. part of a series related tobiomineralization general mineralized tissues remineralisation biocrystallization biointerface biofilm exoskeletons (shells) arthropod exoskeleton cuticle brachiopod shell cephalopod shell cirrate shell cuttlebone gladius lorica choanoflagellate lorica protist shell coccosphere coccolith diatom frustule foraminifera test testate amoebae seashell echinoderm stereom mollusc shell nacre chiton shell gastropod shell small shelly fauna scaly-foot snail shell estuary shells sponge spicule test endoskeletons (bones) vertebrate skeleton bone mineral ossification teeth, scales, tusks etc limpet teeth otolith otolithic membrane scale microfossils tusk calcification amorphous calcium carbonate marine biogenic calcification calcareous nannofossils aragonite oolitic aragonite sand aragonite sea calcite microbial calcite precipitation calcite sea great calcite belt silicification biogenic silica siliceous ooze diatomaceous earth other forms bone bed kerogen alginite oil shale phosphate phosphorite pyrena related mineral evolution in soil mineralization immobilization ballast minerals magnetofossil magnetosome magnetotactic bacteria magnetoreception microfossils engrailed gene druse cupriavidus metallidurans biomineralising polychaetes mineral nutrients microbial mat fossilization permineralization petrifaction burgess shale preservation category there are three phases in the formation of lorica: agglomeration in a natural cast; helical extension; and stabilization. the original meaning of the word is: cuirass, a type of chest armor, originally made of leather, afterward of plates of metal or horn sewed on linen or the like.