BLOOD OF FRESH-WATER MUSSELS 
515 
Table 4. — Per cent of total solids and ash in the blood of four species of North American fresh-water 
mussels, together with total solids and ash in the blood of other animals appended for comparisons 
Scientific name 
Common name 
Fluid used 
Per cent 
of total 
solids 
Per cent 
of ash 
Ratio 
of total 
solids 
to ash 
Locality or 
authority 
Slop bucket. . .. 
Whole blood. . 
0. 3436 
0. 1256 
100 : 37 
Fairport, Iowa. 1 
Do. 
do 
. 4965 
. 1505 
100 : 30 
Pink heel splitter __ - 
.....do 
.4500 
. 1573 
100 : 35 
Do. 
Lampsilis siliquoidea popincnsis 
do 
.4140 
.1820 
100 : 44 
Lynchville, Wis. ! 
.4260 
. 1539 
100 : 36 
European fresh - water 
mussel. 
... .do 
do 
.8540 
.2600 
100 : 30 
Schmidt, 1845. 
Voit, 1860. 
Bottazzi, 1911. 
Myers, 1920. 
Do. 
.3110 
. 1890 
100 : 61 
Octopus 
do 
12. 0300 
2. 9700 
100 : 25 
do 
4. 3300 
2. 8000 
100 : 70 
Washington clam 
do 
4. 2080 
3. 2900 
100 : 80 
Scallop... 
do 
1.7300 
l. 0100 
100 : 58 
Razor clam _ 
do 
1. 7300 
.9900 
100 : 57 
Do. ' 
Soft-shell clam _ 
do. 
1. 6400 
. 9900 
100 : 60 
Do. 
Edible snail. 
._ __do 
3. 9000 
.3000 
100 : 8 
Couvreur, 1900. 
Halliburton, 1885. 
Kruger, 1925. 
Do. 
European crayfish _ 
do 
4. 8600 
1. 1300 
100 : 23 
German carp... _ __ 
. ..do 
13. 4300 
” *Do 
do 1 _ _ ... 
Serum 
5. 2000 
Horse 
25. 0980 
1. 0480 
100 : 5 
Abderhalden, 1911. 
Do. 
Do 
do 
Serum 
9. 7950 
0. 8890 
100 : 90 
1 July 6, 1929. 2 Oct. 10, 1929. 
The total solids found in these samples of fresh-water mussel blood varied from 
0.344 to 0.497 per cent, around an average of 0.426 per cent of the weight of the 
blood. These values lie between the two determinations given for European fresh- 
water mussels — that of Schmidt (1845) being 0.845 per cent for Anodonta cygnea and 
that of Voit (1860) 0.311 per cent for both Anodonta sp. and Unio sp . — and if com- 
pared with the total solids found in the blood of various other animals, both verte- 
brate and invertebrate (see Table 4), show the fresh-water mussels to have a very 
dilute blood. In addition to the animals listed in Table 4, the writers in reviewing the 
existing literature on blood solids have checked some 60 species of animals in all 
without finding any one having as low total blood solids as the fresh-water mussels 
(for general lists see Winterstein, 1925; and Fiirth, 1903). Relatively high total 
solids are the rule in vertebrate blood because of the large numbers of red blood 
corpuscles, not found in fresh-water mussel blood; but even the sera of vertebrate 
blood and the whole blood of invertebrates contain much larger amounts of solids 
than fresh-water mussel blood. 
As the total solids contained in any blood determine the osmotic pressure of 
the fluid of the blood, and are of large importance therefore in regulating the water 
and salt balance in the living tissues of the animal, the very low total solids of fresh- 
water mussel blood suggest a rather close adjustment between the living tissue of 
the fresh-water mussel and the fluid environment in which these animals live. Such 
an adjustment, accomplished through the blood, was established (v. i.) in the experi- 
mental tests in fresh-water mussels. 
Considering the low total solids of the fresh-water mussel blood in connection 
with their habitat of fresh- water — that is, a medium with a relatively low osmotic 
pressure — the low total solids of the soft-shell clam, Mya sp., are of interest, both 
because the fresh-water mussels are regarded as having evolved from shore-dwelling 
marine forms and because Alya is an inhabitant of gravelly mud flats at the mouths 
of rivers (Rogers, 1913), where the salinity of the water would be subject to some 
modification by the outbound -fresh-water. 
15392—31 2 
