brisk east wind is blowing, and the sharpness of outline of hills, woods, and sandy beaches, give a great charm to this spot.
The little pools along the beach were tenanted by several species of fresh-water mollusks. The most abundant was a long turret-shaped Melania, which swarmed in them in the same way as Limnææ do in ponds at home. I found no Limnæa, nor indeed any European genus of fresh-water mollusk, in the Amazons region. After the first storms of February the coast is strewn with large apple-shells (Ampullaria). They are not inhabitants of the pools on this side of the river, but are involuntary visitors, being driven across by the wind and waves with masses of marsh plants from the low land of the opposite shore. A great many are dead shells, and more or less worn. In showery weather I seldom came this way without seeing one or more water snakes of the genus Helicops. They were generally concealed under the heaps of thick aquatic grasses cast ashore by storms; and when exposed, always made off straight for the water. They glided along with such agility that I rarely succeeded in capturing one, and on reaching the river they sought at once the bottom in the deepest parts. I believe these snakes are swept from the marshy land of the western shore with the patches of grass and the Ampullariæ just mentioned. Other reptiles and a great number of insects are blown or floated over in the same way by the violent squalls which occur in January or February. None of the species take root on the Santarem side of the river. Sometimes myriads of Coleopterous insects, belonging to
