The subsequent whorls are shouldered, strongly convex in the middle, but with a smooth concave band below the suture, corresponding to the posterior notch in the outer lip.

On the body whorl these ribs become very oblique below the middle and follow the curve of the edge of the lip, nearly fading out anteriorly.

They become more evident on the lower part of the body whorl and are very faint on the subsutural band, which is more decidedly marked by receding, strongly curved growth lines.

The anterior border of the lip is incurved near the end and obliquely truncate, forming a short, straight siphonal canal.

The absence of eyes and operculum, great size of the posterior sinus, and character of the apex, indicate that this shell represents a new genus, which I purpose to call Pleurotomella.