Functional anatomy of the midgut gland of Gammarus locusta (Crustacea:Amphipoda)

A description of the midgut gland of Gal una us locusta with the aim of using this organ as a complementary tool in ccotoxicological studies vas made. The hepatopancreas is composed of two pairs of blind-ending tubular structures. The thickness and length of these tubules were similar to50 mum and 5 mm, respectively, in adult males (10 12 mm length). The distal part of each tubule is characterized by non-vacuolated E-cells typically exhibiting a relatively high nuclear to cytoplasmatic ratio. The epithelium of the remaining tubules is characterized by abundant columnar R- and F-cells, both similar to40 mum long, Large vacuolated B-cells (similar to60 mum length) were very common along the midgut gland but seemed to increase in number in the proximal region of each tubule. An SEM examination revealed a delicate network of muscle fibres that limits the organ.