II.—The Neogastropod Stomach, with Notes on the Digestive Diverticula and Intestine

Abstract

SynopsisOn the basis of Graham's (1949) work, the stomach of the neogastropods is currently regarded as a secondarily simplified structure exhibiting loss of the cæcum, abbreviation of the major typhlosole and intestinal groove, anterior migration of the opening of the œsophagus, loss of the sorting areas, and in the muricids, of the gastric shield. The present investigations, however, reveal that the stomachs of, at any rate, some neogastropods are less simplified than has been realized. There are well developed typhlosoles, an intestinal groove, gastric shield, and sorting areas resembling those of primitive gastropods.