now some 500 of these _bouchots_ or breeding-grounds in the Bay of Aiguillon, making a fence of 225,000 metres, extending over a space of 8 kilometres, or 5 miles, from the point of St. Clemens to the mouth of the river of Marans. [Illustration: A MUSSEL-FARM.] The Bay of Aiguillon, as has already been observed, is a vast field of mud, and, when left dry at low water, it is impassable on foot. To enable him to traverse it at low water, the _boucholeur_ uses a canoe. This canoe, formed of plain planks of wood, is about nine feet in length and eighteen inches in breadth and depth, the fore-end being something like the usual shape of the bow of a boat. The _boucholeur_ places himself at the stern of the canoe, rests his right knee on the bottom of the boat, leans his body forward, and, seizing the two sides of the canoe with his hands, throws out his left leg, which is encased in a strong boot, backwards to serve as an oar. In this position he pushes his left leg in and out of the mud, and thus propels his light boat along the surface to whatever part of the field he wishes to visit. Notwithstanding the windings and twistings of the confused maze formed on the surface of the bay by the _bouchots_, long habit enables the _boucholeur_, even in the darkest night, to distinguish his neighbour’s establishment in the crowd. The _boucholeur_ uses his canoe not only in transporting his mussels from the _bouchot_ to the shore, and attending to the various operations of the mussel-field, but also in conveying to the proper spot the stakes and hurdles necessary for the construction and repair of the _bouchots_. The furrows left by the canoe in the mud might, in the summer time, by hardening in the sun, render the propulsion of his canoe across the field a very arduous task to the _boucholeur_. Nature has, however, provided an admirable remedy for this possible evil. A small crustacean, the _corophie_, appears in great numbers in the mud-field about the end of the month of April, and during the summer months levels and overturns many leagues of these furrows, and mixes the mud with water, in searching after the innumerable multitudes of worms (annelidæ) of all species that infest the mud. The corophies, which are remarkably fond of these marine worms, pursue them in every direction through the mud; and, by their vigorous efforts to discover their prey, prevent the furrows from forming an obstacle to the progress of the _boucholeur_. This crustacean disappears suddenly, in a single night, towards the end of October.