Crinoid

Clathrocrinus clinatus

• Pennsylvanian
• LaSalle Limestone, Bond Formation
• Pontiac, Illinois, USA

Size: 5.5 cm crown

This species is similar to C. clathratus, except that the brachials articulate at broader angles causing the arms to form a noticeably milder zig-zag pattern. In addition, the calyx is smooth and unornamented with nonimpressed sutures compared to C. clathratus. Also note the prominent spine-tipped anal tube that is visible on this particular specimen.