The structure of glucodigifucoside, newly isolated by the writer and described in the preceding paper, was examined by enzymatic decomposition. The enzyme used was the same enzyme isolated from a snail (Euhadra quaesita DESHAYES), described in Part IV of this series. It was found that hydrolysis under a general condition afforded digitoxigenin, with both glucose and fucose hydrolyzed, but under the same conditions as those used in the partial decomposition of gitostin to form digitalinum verum, by shortening the duration of hydrolysis, glucose alone was found to be hydrolyzed, affording a digiproside. From these results, it was established that glucodigifucoside is a diglycoside formed by the bonding of one mole of glucose to digiproside. It was also found that this digiproside is also hydrolyzed by this enzyme and that this enzyme also hydrolyzed fucose.