i think the story is the distinction made between two different world one the world from the point of view of snail and the world of the people wandering about the flower bed.
in the beginig of the story we understood that the subject matter of the story is KEW GARDEN...people came to visit the garden.the people over there were roaming aimlessly and the life here like a blue butterfly. in other word human being were leading aimless irregular life,whle on the other hand snails appears to have definite goal in front of it.the people where present there were all preoccupied themselves with old memories but the snail is here the only one whose direction is snail itself.
the snails journey through the floerbed is judt one activity among the many that makes the garden scene so dense with life and complexity.
net