The histological study of the digestive gland of the two cephalopods, Eledone cirrosa and Sepia officinalis, has allowed to distinguish the different cellular types and their functions: enzymes secretion, absorption, excretion, lipid storage. During digestion, the abundance in proteinaceous inclusions or "boules" (proteolytic enzymes) undergoes variations. The beginning of the digestive process is characterized by an almost total absence (meaning secretion), the end by an accumulation of such "boules". Some information about the fine structure of the digestive gland of Eledone are given, and compared with the ultrastructure of the digestive gland of Sepia. Pinocytosis exists in the cells of both species. These observations constitute arguments in favour of the existence of intracellular digestion in the Octopod. Such is already known to be the case in Sepia (Boucaud-Camou and Yim, 1980). The three different cellular types present in the tubules might be in fact different figures corresponding to different stages of the same cell, the "cellule a boules". This digestive cell is actually the only active cellular type and cumulates all the functions imputed to the digestive gland. |
