« It was in August 1891 that I collected, in the middle of fishing residues, the two living individuals who served me to make these observations: they had been caught, off Carry-le-Rouet (near Marseille), on bottoms of Zostera and coralligen, at a depth of 25 to 30 meters. These individuals, put in fresh sea-water, were not slow to spread themselves and start up; they were very vigorous; so I could keep them alive for a week or so. […] The Neosimnia spelta in action, well spread, as I have shown from the front and in profile […] shows the lobes of its mantle thrown back on the sides of the shell; these lobes rise much less on each side than is observed in the Cypraea. These organs are smooth, slightly sinuous and, joining together in front and behind, they form, in these two points, on the side of the ventral surface, a kind of cavity. » – op. cit p.6.