Galactogen has been reported in the albumen gland of pulmonate snails such as Helix pomatia,[4] Limnaea stagnalis,[5] Oxychilus cellarius,[6] Achatina fulica,[7] Aplexa nitens and Otala lactea,[8] Bulimnaea megasoma,[9] Ariolimax columbianis,[10] Ariophanta,[11] Biomphalaria glabrata,[12] and Strophochelius oblongus.

[15] In adult gastropods, galactogen is confined to the albumen gland, showing a large variation in content during the year and reaching a higher peak in the reproductive season.

[2] During the reproductive season, this polysaccharide is rapidly restored in the albumen gland after being transferred to the eggs, decreasing its total amount only after repeated ovipositions.

[17] This polysaccharide has been identified in the Golgi zone of the secretory cells from the albumen gland in the form of discrete granules 200 Å in diameter.

[1][20] Apart from the albumen gland, galactogen is also found as a major component of the perivitelline fluid from the snail eggs, comprising the main energy source for the developing embryo.

[3] Other analyses in Helix pomatia suggested a dichotomous structure, where each galactopyranose unit bears a branch or side chain.

[15] Phosphate-substituted galactose residues are found in the galactogen of individual species from various snail genera such as Biomphalaria, Helix and Cepaea.

[19] Glycogen accumulates in autumn as a general energy storage for hibernation, whereas galactogen is synthesized during spring in preparation of egg-laying.

Given that carbohydrates retain water, the high amount of this polysaccharide would protect the eggs from desiccation from those snails that have aerial oviposition.

This fact led to consider galactogen as part of an antipredation defense system exclusive of gastropods, deterring predators by lowering the nutritional value of eggs.