The broad spaces that separate these cords are marked by numerous fine, raised, axial threads.

They are marked with a strong peripheral sulcus which is crossed by numerous axial threads.

The spaces between the cords are marked by numerous slender, axial threads.

The grooves separating these cords are marked by many slender axial threads.

The grooves on the base are crossed by numerous slender axial threads.

The broad spaces between these keels are crossed by slender, raised axial threads.

The grooves between the spiral cords are marked by numerous fine, axial raised threads.

The latter are somewhat broader than the keels and crossed by many, very slender raised axial threads.

The deep channel between the two keels is marked by very feeble slender axial threads.

The impressed grooves are crossed by numerous slender axial threads.