Neithea theodori

These animals had a medium to large shell (large being about 3cm), it is almost equilateral, very broad, and its height almost equals its length.  It also has a polygonal outline, the ventral margin is sub-semicircular with six definite angles, and the ears are missing.  This species is slightly different then the Neithea texana which is more globose in shape; it also has a greater difference in height between the low and raised ribs, and it has a more sinuous ventral margin.  This specimen was found in the Georgetown Limestone, Austin, Texas.

 
This specimen is suffering from efflorescence of salts often referred to as 'Byne's disease' . It is now housed with measures to stabilize the humidity.