234 
the Echinocyamus-community, in more shallow water along the 
shore between the Zostera and the Abra community and on the 
banks. See the chart p. 222. 1091 of the samples were from the 
Abra-community, 409 from the Echinocyamus-community. P. 004 
is a list of the different species of the Abra community found in 
the summer 1919 with the number of specimens of each pr. m 2 
(the middle column). P. 228 is a list of the species of the Echino¬ 
cyamus-community also with the number of specimens pr m 2 . 
3. On the Abra-community of the Løgstør Bredning the Dan- 
ish Biological Station every spring and every autumn takes 18 
samples with the bottom-collector. In the list p. 224 the number 
of specimens pr. m 2 , found by means of the 18 samples (the first 
and the last column) is noted for a comparison with the results 
from the 1091 samples. It is obvious that the results agree in the 
case of the unfrequent species (i. e. species with a density smaller 
than 1 pr. m 2 ); in the case of the very common species (i. e. more 
than 10 pr. m 2 ) the results agree more moderately, but with regard 
to the rather common species (i. e. 1 — 10 pr. m 2 ) the conformity 
is still less complete, because these species often belong to the 
epifauna or have no uniform distribution (for instance Cardium 
fasciatum). 
4. The species of the Abra-community are extending to a 
certain degree into the Echinocyamus-community and vice versa. 
The density of the species of the Abra-community in the Echino¬ 
cyamus-community is however inconsiderable. Some of the species 
are still more definitely confined to the Abra community, for instance 
Corbula gibba , of which 99,3 % of the specimens, Nassa pygmæa, 
of which 98,4 %> and Philine aperta, of which 97,3 % were from 
the Abra-community. The species the most confined to the Echino¬ 
cyamus-community are Cerithium reticulatum, of which 98,7 °/o of 
the specimens, and Echinocyamus pusillus, of which 97,8 °/o were 
from the Echinocyamus-community. It has been proved that the 
mussels trom the Abra-community are less uniformly distributed 
than the gasteropods, annelids and ophiurids of this community. 
5. The number of specimens of the very common species in 
the Abra-community is calculated approximately. It varies from 
2—12 billions. See p. 233. 
6. It has been proved that the first and second of Monards 
