« Shell subglobose or very convex, entirely smooth below, with three longitudinal ribs above, like truncated forwards and backwards; the lateral appendages of the shell very little pronounced and forming two small points on each side of the median point which is very big. The fins of the animal are bilobed without lateral expansions. […] discovered by Mr. Lesueur in the Antlantic Ocean, near the Barbados. » – H. M. D. de Blainville: “Hyale” in Dictionnaire des sciences naturelles vol. XXII, Paris 1821, p.81.

« …the liveliest and most petulant of all [the species of the genus]. It swims by fluttering with a speed that barely allows to follow it, let alone to distinguish the movements of its wings. In its swimming it seems to describe curves, or, at least, irregular lines. Rarely have we seen it follow a straight line. Besides, it seems very common in the area where it lives. »