BIOLOGY AND NATURAL HISTORY 241 



1950, however, the price per pound had fallen to less than $1.00. Most 

 Japanese factories are located in the cold, mountainous prefectures of north- 

 ern Japan. Agar is manufactured only from December through February, 

 when air temperatures will cause the agar gel to freeze, a vital step in the 

 dehydration and purification process. Few factories have mechanical refriger- 

 ation equipment. In 1946, it was estimated that about 600 small agar factories 

 would resume operations with an average of eight employees each. Virtually 

 everything is done by hand. 



Approximate consumption of agar on the principal continents for a typical 

 pre-war year (1939) is shown in Table 4. 



TABLE 4 



Agar Consumed in 1939 on the Three Principal Continents 



Tons 

 North America 266 



Europe 660 



Asia 611 



Since consumption of agar in Europe is more than double that used in 

 the United States (or even in both North and South America), it would 

 appear that there is still a great potential market for phycocolloids in the 

 Americas that has not yet been served. 



BIOLOGY OF NORTH CAROLINA SEAWEEDS 



Economic seaweeds of North Carolina can be collected from about May 

 first through December of a good year. The principal environmental factors 

 which influence growth and variation in abundance from year to year are 

 water temperature, salinity, and concentration of nitrogenous salts and 

 phosphates. Factors that control individual species are not known. 



Gracilaria jolitjera reached commercial abundance in early May near 

 Beaufort in 1945. The peak of abundance occurred in June, and in July it 

 had begun to decline. In 1946 the species developed later, reached much 

 greater abundance (Table 2), and was collected through September. It 

 appears to be a species that grows well at lower average salinities than does 

 G. conjervoides, as salinities were unusually low during August, 1946, and 

 G. conjervoides failed to develop in quantity. G. joliijera is to be found 

 farther up estuaries than G. conjervoides. Although all plants of G. joliijera 

 grow attached at first, large quantities may be found adrift at the peak of 

 the season. The species is found along the entire Atlantic coast of the 

 United States. 



Hypnea muscijormis overlaps the season of G. joliijera although the peaks 

 of abundance of the two may not coincide. Collection near Beaufort usually 



