ve Gao possesses a distinct aquatic people, the Somnos or Bosos, who
earn their living as fishermen and boatmen on the river. They spread
their villages along the Niger and its tributaries, and occupy separate
quarters in the large towns like Gao and Timbuctoo. They are creatures
of the river rather than of the land, and show great skill and endurance
in paddling and poling their narrow dugouts on their long Niger
voyages.[712]

Reference has been made before to the large river population of China
who live on boats and rafts, and forward the trade of the vast inland
waterways. These are people, differentiated not in race, but in
occupation and mode of life, constantly recruited from the congested
population of the land. Allied to them are the trackers or towing crews
whose villages form a distinctive feature of the turbulent upper
Yangtze, and who are employed, sometimes three hundred at a time, to
drag junks up the succession of rapids above Ichang.[713] Similarly the
complex of navigable waterways centering about Paris, as far back as the
reign of Tiberius Caesar, gave rise to the _Nautae Parisii_ or guild of
mariners, from whom the city of Paris derived its present coat of
arms--a vessel under full sail. These Lutetian boatmen handled the river
traffic in all the territory drained by the Seine, Marne, and Oise.
Later, in the reign of Louis the Fat, they were succeeded by the
_Mercatores aquae Parisiaci_, and from them sprang the municipal body
appointed to regulate the river navigation and commerce.[714]

[Sidenote: River islands as protected sites.]

The location of the ancient tribe of the Parisii is typical of many
other weak riverine folk who seek in the islands of a river a protected
position to compensate for their paucity of number. The Parisii, one of
the smallest of the Gallic tribes, ill-matched against their populous
neighbors, took refuge on ten islands and sandbars of the Seine and
there established themselves.[715] Stanley found an island in the Congo
near the second cataract of Stanley Falls occupied by five villages of
the Baswa, who had taken refuge there from the attacks of the
bloodthirsty Bakuma.[716] During the Tartar invasions of Russia in the
thirteenth and fourteenth centuries, bands of refugees from the
surrounding country gathered for mutual defense on the islands of the
Dnieper River, and became the nucleus of the Dnieper Cossacks.[717] The
Huron tribe of American Indians, reduced to a me