The shell figured differs from Basillisa costulata Watson, 1879 (synonym of Ancistrobasis reticulata (Philippi, 1844) ) in the less flexuous radiating costae, which are nearly equal to the interspaces in width, and in the smaller number of spiral ridges, which are about ten on the base and seven to nine on the upper surface of the whorls.

If I am correct in the identification, this material enables me to add a good deal to the knowledge of the species and genus.

The dried remains of the animal in one specimen bear a pellucid multispiral operculum a little more circular in outline than that of Seguenzia, but otherwise precisely like it.

The protoconch in this form gives the impression, after a very close scrutiny of several fresh specimens, that it is really laid at right angles to the original axis and half immersed in the first post-nuclear turn.

This is masked by the fact that the protoconch proper occupies less than a single turn, and appears thus more normal than it really is, if my suspicions are correct.