However, the same relationship can be found in Table 8 , which
is based on the average values of similar species.
l.
Muscle consistently has the lowest specific activity
regardless of species.
Ce
"Liver" or digestive gland is the only tissue sampled,
other than muscle, which is not subject to external
contamination.
It rarely has a higher specific activity
than the digestive tract and is always more radioactive
than muscle.
The relative specific activity of the gill varies with
the species.
In the clams the gills,
which are the
food gathering organ, have the highest activity, exclusive of the digestive tract with its content.
In those
snails with a gill the "liver" is the more active.
The
liver is also more active than the gill in the crabs.
The digestive tract with its content is usually the
most radioactive portion.
Its activity is highly vari-
able, however, even within a species from the same
station.
Shell and carapace are also highly variable in specific
activity.
The following rankings of tissues in descending order
of specific activity with individual exceptions are:
a.
Clams:
(1)
2
3
4
5
digestive tract (visceral mass with
ill
contents)
Hhiver"
mantle
muscle
-~ 4 -
ye met
An