51 
l. Each species of the animals was weighed and preserved separately. 
This method was used for the following localities: Thisted Bredning, Sallingsund, 
the waters east of Fur, Skivefjord, Risgaards Bredning, Hvalpsund, the waters east 
of Venø, Oddesund, Lavbjerg Bredning, Bramsnæsvig and Isefjord. 
It was determined by analysis, how much organic dry matter each single 
bottle contained. It was partly determined, how much there was in the alcohol 
by measuring its quantity and evaporating 10 or 20 ccm. to dryness and weighing 
the residue. It was further determined how much organic dry matter was found 
in the animals, by freeing them from the shells and crustaceous matter on the 
whole, and drying them either as a whole or a definite portion of them. 
The molluses were freed from their shells by simply picking them out 
with forceps. This method was also used for the small gastropods, e. g Åcera. 
On the other hand, the Echinoderms were freed of their calcareous matter by 
extraction with dilute hydrochloric acid and washing out with distilled water. It 
is naturally impossible to prevent some organic material being lost in this way; 
but the amount is scarcely of any importance. 
The animals were first dried at 60%, until the greater part of the water 
had been removed, and then at 100", 
It appeared in all the determinations, that relatively large quantities of dry 
matter occurred in the alcohol. This was due partly to the fact, that a good deal 
of the salts contained in the animals are washed out in the alcohol. Now as a 
matter of fact, the salts do not belong to the »organic dry matter«, but it would 
make the method much more complicated if they were determined and deducted 
in each single case; I have preferred to include them therefore. As we are dealing 
essentially with relative values, this has scarcely any importance. 
From these determinations we learn how much organic dry matter a 
definite rough weight of a definite species contains, and we can thus calculate the 
quantity of dry matter in percentage of rough weight. 
The results are given in the following table: 
Solenkpelbieidus ere eee 8.3 Nassarretiulataeeseenes i e 9.6 
NGU ao da EN 5.3 Philme ta persere reen 14.0 
Small? Mya truncata 1 RES 6.6 Aceran bulter eee NS 
Large - SR TD PEST 10% ub eWw oms ae ene ( 
Car drums fas era me 7.7 OfherkChætopod seere 19.9 
Abraalbar se vs ses DEER 8.5 APR Ode REESE SENGE 16.1 
MBrochuskemerards rer 6.5 Betina rn ae se 160 
Bittormaklittore see er eee Br Ophiosly phase 3.s 
Bucenumkundsun see 11,2 JENS ES) HE ERR SEE OSSE EDER 7.2 
The intention with these results was essentially, that they should help to 
lighten the work in future, as we should only require to determine the rough 
weight. From the percentage of dry matter we could then estimate the quantity 
of dry matter. These percentages for the dry matter must however be regarded 
as merely provisional. How much they vary in the different seasons of the year 
and in the different localities, has as yet been too little investigated. 
2. The species without weighing were placed together in a bottle. This 
method was used in all the other cases, with the North Sea samples, a number of 
