What is "riccius"

Riccius is a lunar crater that is located in the rugged, southeastern part of the Moon's near side. It lies within one crater diameter southeast of the crater Rabbi Levi. To the east-northeast is Stiborius and due south is Nicolai.

This formation has been so heavily bombarded by subsequent impacts that it is nearly unrecognizable as a crater. Only the western and southwestern parts of the rim remains intact, the remainder having been completely obliterated by small craters. These craters also occupy parts of the northern and southern floor. Only a section in the northeast and near the intact western rim remain unmarked. This is perhaps the most defaced crater formation on the Moon that possesses an eponym.