The mantle cavity of some of the Erycinidae, Montacutidae and Galeommatidae with special reference to the ciliary mechanisms

Abstract

The habitat, external appearance and habits of members of the Erycinidae, Montacutidae and Galeommatidae, three families included in the order Leptonacea, have been investigated and are described.The ciliary currents of the gills, palps, visceral mass, foot and mantle are described in detail.There is some reduction in the shell in this order. In Kellia, Lasaea, Montacuta and Mysella the shell is external and the adductor muscles are well developed. In Galeomma the shell and adductors are reduced, and in Devonia the shell is also partially covered by the mantle.The foot is modified, and all members of this order progress on the flattened ventral surface of the foot which forms a creeping sole. The burrowing habit is lost.