116 



THE AQUAKIUM, JULY, 1894. 



England, wliere the great gray slugs 

 will ruin a garden in one night, if the 

 gardener' is not daily on the watch. Our 

 own strawberries sometimes suifer, but 

 a border of sawdust, sand or ashes 

 around the bed is an adequate protec- 

 tion in dry weather. In trying to cross 

 it the marauders become so entangled 

 in the particles adhering to their slimy 

 bodies, that they exhaust themselves in 

 the attempt to get free. They also are 

 very fond of fungi, including many 

 poisonous kinds. 



At the first hint of frost our snail 

 feels the approach of a resistless lassi- 

 tude, and, creeping under some mould- 

 ering log or half-buried bowlder, it at- 

 taches itself, aperture upward, by ex- 

 uding a little glue, and settles itself for 

 a season of hibernating sleep. With- 

 drawing into the shell, the animal 

 throws across the aperture a film of 

 slimy mucus, which hardens as tight as 

 a miniature drum-head. As the weather 

 becomes colder, the creature draws it- 

 self a little farther in, and makes 

 another " epiphragm," and so on until 

 often five or six protect the animal 

 sleeping snugly coiled in the deepest re- 

 cesses of his domicile. 



This state of torpidity is so profound 

 that all the ordinary functions of the 

 body cease — respiration being so entire- 

 ly suspended that chemical tests are 

 said to discover no change from its 

 original purity in the air within the 

 epiphragm. Thus the snail can pass 

 Avithout exhaustion the long, cold 

 months of the North, when it would 

 be impossible for it to secure its custom- 

 ary food. The reviving sun of spring 

 only interrupts this deep slumber, and 

 the period of awakening is therefore 

 delayed with the season, according to 

 the varying natures of the different spe- 

 cies. At any time, however, an artificial 



raising of the temperature breaks the 

 torpor, the warmth of the hand being 

 enough to set the heart beating. Ex- 

 treme drouth also will cause snails to 

 seal their doors hermetically, without 

 even hanging a card basket outside. This 

 is to shut off the evaporation of their 

 bodily moisture, and happens in mid- 

 summer, hence it is termed aestivation. 

 Certain slugs (Testacellidae), which 

 have no shells, are able to protect them- 

 selves under the same circumstances by 

 a gelatinous appendage of the mantle, 

 which, in case of sudden change of 

 temperature can be extended like an 

 outer mantle, so to speak, from its place 

 of storage, under the "buckler," and 

 having wrapped themselves, they bur- 

 row in the soil. 



AQUATIC PLANTS AT HOME. 



In the Amazon region, which com- 

 prises such vast extents of water, there 

 must necessarily be a large number of 

 aquatic plants, and some of these are 

 very ornamental. In voyaging by canoe 

 through miles upon miles of the water 

 ways which thread all of the '' varzea," 

 for so the land subject to overflow with 

 the annual rise of the river is called, 

 one finds many curious species. In the 

 main Amazon there are few, though at 

 times one sees bays full of the pretty 

 *' Eichornia speciosa" for the banks 

 are constantly changing, the current is 

 rapid and there is little opportunity 

 for any permanent growth to establish 

 itself. But the " varzea" is full of lakes, 

 many of which are very large, and even 

 where the banks of the Amazon are 

 high, there are usually some miles back 

 from the river clear water lakes. All of 

 these lakes communicate with the main 

 river, either directly or indirectly by 

 streams connecting one with another. 



