34 LIMNAZIDZ. 
This pretty little shell is found in ponds and ditches 
widely distributed, but it is said to be local. It 
forms an attractive object in an aquarium as it floats 
on the top of the water with its dark blue foot upper- 
most. 
2. P. FONTINALIS (frequenting springs). 
Sinistral, oval, very thin, glossy, semi-transparent, 
greenish horn-colour; whorls four to five, tumid; spire very 
short, but pointed obtusely. 
This shell, which is very common in running water 
and ponds on weed, is often disappointing when the 
animal is removed. When wet with the animal inside 
the shell appears iridescent, but when clean and dry 
is often dull. 
This species is perhaps more interesting as an 
inmate of an aquarium than the last, as it is un- 
usually active for a mollusk, and amusingly quarrel- 
some. When two individuals meet, they engage in 
(seemingly) angry combat, jerking themselves and 
their antagonist to and fro like wrestlers! They spin 
colourless threads of mucus, along which they crawl 
and practise gymnastics. 
Var. I. inflata. Much larger. 
Var. Il. curta. Spire very short. 
Var, III. oblonga. Spire produced. 
