Brachionus plicatilis (L-type rotifers) has a typical lorica length of about 160 µm. This species is euryhaline, capable of thriving in salinities of 5-40 ppt. Brachionus rotundiformis has a typical lorica length of about 90-150µm. This species is also euryhaline. It's basically the size that differentiates them. The lorica is the rigid structure that gives them their body form and protects them. Lorica is what the Romans called their body armor.