30 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 mollusks. 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 Linmsea, 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 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 AmpullariaB 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 



