Description: Cortical shell with closelyspaced mammae. Mammae uniform in size, moderately large, high in relief, distal surface rounded, hexagonal or subcircular in outline, with long primary spine originating from center of each mamma. Primary spines slender, circular in axial section. Each mamma with five to seven short rays

connection directly to adjacent mammae of linking with rays from sur

rounding mammae. Rays single, bifurcate, or trifurcate. Mammary pore frames poorly developed, with thin bars connecting massive rays and forming small subtriangles beneath mammae. Intermammary pore frames large, regular in size, mostly triangular and tetragonal in outline.

Remarks:Praeconocaryomma decora is very similar to P. immodica Pessagno and Poission (1981) by having a cortical shell with large rounded, closely spaced mammae and by having primary spines circular in axial section. These two species can be distinguished by different pattern of intermammary pore frames.

Etymology Decorus-a-um (Latin, adj.) graceful.

Praeconocaryomma decora was named by Yeh (1987). Its type specimen is NMNS (000035) and is a 3D body fossil. Its type locality is Suplee-Izee area, OR-600A, which is in a Toarcian marine tuff/limestone in the Hyde Formation of Oregon.