Belemnotheutis phragmocones

Description:

Description: English: Left:Perfect form of peristome, a; though much compressed, the cavity of the chamber, partially filled with clay, is well-defined Right:This specimen is also perfect, but in consequence of its position in the clay, only one-half of the basal or upper part of the margin of the peristome (a) is visible. Date: 1848. Source: Philosophical Transactions of the Royal Society of London. For the Year MDCCCXLVIII Part I. Author: Gideon Mantell.