THE VARIED ROLES OF SNAILS - National Universities Commission

organs of some species and found significant differences in
the dimensions of the preputium and penis sheaths. Wright
and Rollinson (1979) examined the possibility of using isoelectric
focusing techniques in differentiating snail species
and they found no clear enzyme type for certain characters.
However these studies made enough in road to allow them
suggest that biochemical taxonomic methods could be used
to effectively differentiate the species. Jelnes (1979) using
electrophoresis came to similar conclusions. Other methods
that show promise are distribution of micro-sculpture on
the shell, presence or absence of aperture bands, number of
whorls, and characters of the radula.
Biometric multivariate analyses of phenotypic characters;
stepwise discriminant analysis of morphological characters
of the shell and pairwise discriminant analyses are
statistical tools that have been used in snail taxonomical
studies. In these analyses, shape of shell, length of shell
diagonal, width of shell at the level of the last suture, length
of body whorl above the aperture and width of the shell are
the factors that could be used to load the characters
important in separating the Genera and species.
i. ECOLOGY OF GASTROPODS
Gastropods live in every conceivable habitat on earth. They
are found in virtually all habitats ranging from high
mountains to deserts, and to the rain forests. They are also
found from the tropics to high altitudes. Many snails are
benthic and mainly epifaunal, but some are planktonic.
There are many microspecies of gastropods too numerous
to count.
It has also been found that the relationship between snails
and plants are often mutualistic deriving a lot of benefits
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