Ultrastructural and histochemical studies of the digestive system of Pholoe minuta (Polychaeta: Sigalionidae)

Abstract

This work reports on the fine structure and histochemistry of several regions of the alimentary canal in Pholoe minuta (Fabricius, 1780). Particular emphasis is placed on the elaborate secretory cells (tryptophan-containing secretion) associated with the pharyngeal jaws. Mucus gland cells were located and described for the oesophagus (acid mucins), pharynx papillae (sulphated acid mucins), pharynx luminal lining (mixed acid mucins) and the intestine (mixed acid mucins). Enzymic gland cells (zymogen-like secretory granules) were identified in the luminal lining of the pharynx and in the intestine. Lysosome-containing cells (presumably absorptive) were described in the intestine. Glycogen reserves were observed along the coelomic peritoneum and a seasonal pattern for their deposition and utilization is briefly discussed.