|Zur Embryonalen Entwicklung von Lamellaria perspicua L.: (1) (Gastropoda, Prosobranchia, Mesogastropoda, Lamellariacea)|
Fioroni, P.; Meister, G. (1976). Zur Embryonalen Entwicklung von Lamellaria perspicua L.: (1) (Gastropoda, Prosobranchia, Mesogastropoda, Lamellariacea). Cah. Biol. Mar. 17(3): 323-336
In: Cahiers de Biologie Marine. Station Biologique de Roscoff: Paris. ISSN 0007-9723, more
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The cleavage of the eggs of Lamellaria perspicua L. (diameter: 230-300 p.m) is inequal and characterized by the formation of 4 large macromeres. The gastrulation is epibolic. In the preveliger-stage, the prospective endodermal parts of the midgut [stomach, midgut-gland (hepatopancreas, liver), hindgut] already show histological differences. A part of the midgut-anlage, rich in vitellus, is not organogenetic and dissolves; the delivered yolk-substances are stored and resorbed in the left midgut-gland. In the preveliger, the early segregation of the periostracum [anlage of the larval conch (= Echinospira) ] is seen, which detaches from the epithelium of the shell gland, covered by another fine lamella, as anlage of the adult conch (teloconch ) . The larval kidneys appear late and are only differenciated in the intracapsular veliger. The pallial organs, the radular pocket and the gonades are developed after hatching (shell-diameter: 350 µm; all the yolk is resorbed) during the long planctonic period which enables an intensive growth of the Echinospira-larva.