THE YELLOW PIGMENT CELLS OF HYDROBIA ULVAE (PENNANT) (MOLLUSCA : PROSOBRANCHIA)

The distribution of yellow pigment cells in the veliger larvaeand post-metamorphic snails of Hydrobia ulvae has been recorded.The number of cells increases with the size of the snail andthe pigment is characteristic of the foot of the veliger larva,and the foot, mantle, tentacles and penis of adult snails. Thecells contain numerous, double membrane-bound vesicles and havea highly granular cytoplasm. The absorption spectra of acetoneand methanolic HC1 extracts show single peaks at 337 and 392nm respectively, while chloroform extracts show peaks at 249,274 and 283 nm with an inflexion at 293 nm. The pigment hasa pale green fluorescence in ultraviolet light. The resultsof feeding and starvation experiments using larval and post-metamorphicsnails lead to the hypothesis that the pigment is a waste productof metabolism which is stored in the vesicles of the cells (Received 3 January 1979;