262 



THE MICROSCOPE. 



found in cellars ; but, on examination, it will be found to differ from 

 these creatures in being exactly the same on both sides ; or, in the 

 language of a naturalist, having neither spine nor column. The animal 

 belonging to this shell is extremely like a snail, when it is crawling 

 with its tentacles extended ; but it is much smaller in all its parts. It 

 is found in ditches and ponds. The amber snail (Succinea amphibia) 



fig. 114. The Amber Snail. Physafontinalis. Moor Snail and Mountain Bulimus, 



has a beautiful transparent shell of a light amber colour ; and it is from 

 this that it derives its scientific name as Succinum signifies amber. 

 The puddle-mud snail (Limnceus peregra) is also very generally found 

 in this country. Its shell bears considerable resemblance to that of 

 Succinea; but it is less transparent, and has a more horny look. The 

 shells of all the species of Limncea have the aperture on the right hand, 

 and the plait on the left hand, which distinguishes them from Succinea. 

 Another kind of pond-snail, called the stream-bubble shell (Physafon- 

 tinalis), is distinguished from Limnceus by its opening being on the left 

 handinstead of the right. 



fig. 115. Limnoea stagnalis. 



It is extremely curious to watch the development of the spawn of 

 these animals under a magnifying-glass. The spawn of the water-snail 



