Research Product

Egg capsule micromorphology of eight species of neogastropods (Chicoreus florifer dilectus, Phyllonotus pomum, Cantharus multangulus, C. cancellarius, Conus floridanus floridensis, C. jaspideus stearnsi, Granulina ovuliformis, and Marginella aureocincta) was studied with light microscopy by examining very thick, toluidine blue stained sections. Laminae exposed by fracturing the sections, and their reactions to the stain, provided the characters used to describe micromorphology. The results showed that muricaceans and buccinaceans have complex but microstructurally similar egg capsules, while conids and marginellids have egg capsules with taxonomically distinct microstructural characteristics. In the Muricacea and Buccinacea, four structural laminae of similar origin and function are usually present in the capsule wall, the second from the outermost having the most complex pattern of fibers and the greatest thickness. The third outermost lamina is continuous with one or more components sealing the escape aperture. In some buccinaceans, only a trace of the third lamina exists in the wall. Four layers, including one or two mucoid plugs, close the escape aperture. Conid egg capsules differ in that they include only three structured laminae in the capsule wall and three layers, including a mucoid plug, sealing the escape aperture. Microstructure and fiber pattern in the middle lamina are probably unique to this family. Egg capsules of marginellids have a distinctive thin, dense wall not separated into laminae and lack an escape aperture closed by a mucoid plug. There is a preformed suture that fractures at hatching in the wall of most marginellid egg capsules.