Cambrothyra

Cambrothyra (not to be confused with "Cambrorhytium") is a Lower Cambrian coeloscleritophoran from China. The fossils are hollow cones with porous walls that had an originally fibrous aragonitic mineralogy. These conical sclerites were generally not connected to other sclerites; only occasionally are they paired or twinned.
The genus comprises the sole species "C. ampulliformis".