No. 384.] REVIEWS OF RECENT LITERATURE. 953 
sufficient. It is further estimated that on the basis of total dry weight 
1 copepod = r35 Peridinidæ = 1687 diatoms ; when, however, only 
the ash-free matter is made the basis of comparison, 1 copepod = 127 
Peridinidz = 4407 diatoms. As the result of the analysis of 15 dif- 
ferent catches, the chemical composition of the Copepoda, Peridinide, 
and of the diatoms was ascertained to be as follows, the amounts of 
the constituent substances being expressed in parts per hundred 
of the total dry weight. 
ALBUMEN. CHITIN. FAT Rea oy ah AsH. 
Copepoda . 59.00 4.70 7.00 20.00 9.30 
Peridinidæ . 13.00 — 1.40 80.601 5.00 
Diatoms? . 10.75 — 2.50 21.50 65.25% 
The autumn and winter planktons of the Baltic are quite similar 
in their chemical composition, which is about midway between that 
of “rich pasturage” and green lupines, as shown in the following 
table. 
Per Cent Dry WEIGHT. ALBUMEN. FAT. ase ASH. 
Rich pasturage 20.6 4.5 64.6 10.1 
Autumn plankton 20.2-21.8 2.1-3-2 60.—68.9 8. r z 
Green lupines . 20.6 2.6 72. 
An October oe rich in Peridinide, principally Ceratium, 
differs materially from all land products used as fodder, in the small 
content of fat and the relatively large amount of carbohydrates 
(cellulose principally). Its nearest chemical counterparts among the 
products of the soil are to be found in rye straw and meadow hay. 
P ggg rol nig ALBUMEN. Far. Potala CELLULOSE. AsH. 
Rye straw 3:5 1.5 38.8 51.3 4-7 
Ceratium plankton 13.0 1.3 39.0 41.5 5-2 
Meadow hay 13.6 3-2 48.2 26.8 8.2 
1 About 50 per cent of this is cellulose. 
2 Principally Chaetoceros. 
bout 50 per cent of this is SiO,. 
