Development of the Aplacophorous Mollusc Neomenia carinata Tullberg

Abstract

PRESENT-DAY authorities agree that, within the Mollusca, the chitons (or Polyplacophora) are closely related to the solenogastres (or Aplacophora). An important item influencing this view is the description, by Pruvot¹, of the development of seven overlapping, dorsal, plate-like spicules in the metamorphosing larva of the solenogastre, Nematomenia banyulensis. The appearance of these spicules has been considered to be a reminiscence of a chiton-like ancestor and, no doubt, has influenced many authors in coming to the conclusion that the solenogastres are degenerate chitons. Pruvot's description was based on observations on a single larva, but nonetheless the figure he gave of this developmental stage has been widely reproduced in general works.