STRUCTURE OF THE GLAND FILTERS IN THE PYLORIC STOMACH OF PENAEUS JAPONICUS (DECAPODA: PENAEIDAE)

Abstract

ABSTRACT The gland filters of Penaeus japonicus are two seta-lined ampullae which originate from the thickened cuticle lining the epithelium of the ventral pyloric stomach. The two ampullae are arranged in an inverted V shape from the dorsal to the ventral surface. Each ampulla consists of an upper ampullary half and a lower ampullary half, with a slight dilation between them. The setae lining the upper and lower ampullary halves form a setal screen guarding and guiding the passage of food. Masticated fine food particles from the cardiac stomach can pass through a small dorsal slit above the interampullary ridge and then flow into the two lateral ampullae. The fine food particles enter the lower ampullary channels and then longitudinal grooves which are confluent at the posterior of an ampulla. The width of the seta-lined lower ampullary channels is about 1.0 μm, and the width of the longitudinal grooves is approximately 16 μm. In this study, the detailed structure of the gland filters in Penaeus japonicus is described for the first time.