80 
SANTAREM. 
Chap. I. 
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 moUusks. The most 
abundant was a long turret-shaped Melania, which 
swarmed in them in the same way as Limnsese do in 
ponds at home. I found no Limnsea, nor indeed any 
European genus of fresh-water moUusk, 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 con- 
cealed 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 Ampullarise 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 
