part_of part of part of starts during midbrain multi-tissue structure torus semicircularis UBERON:2000599 XAO:0004590 xenopus_anatomy Multi-tissue structure that is part of the midbrain and develops from the alar plate. It is located dorsal to the lateral tegmentum where it extends into the medial tectal ventricle and receives ascending sensory octavolateralis input. NF stage 22