952 THE AMERICAN NATURALIST. [VoL. XXXII. 
too minute to supply any information respecting the form of the 
burials,” or, what is much more important, the character of the 
skeletons themselves, from which the racial affinities of the people 
might perhaps be determined. Scarcely second in interest to the 
long-sought “ Rosetta stone of the Mayas” would be a moderately 
large series of Maya skeletons in a fair state of preservation. 
FRANK RUSSELL. 
GENERAL BIOLOGY. 
Variation in Seedlings. — Professor Herbert L. Jones? found in 
Cambridge, Mass., a sycamore maple, Acer pseudoplanatus, which pro- 
duces seedlings showing a large number of abnormalities. The coty- 
ledons show a tendency to be doubled, and all grades of doubling 
were found from a mere notch at the distal end of one cotyledon 
to four complete seed-leaves. Where one cotyledon is completely 
doubled, the plumule usually consists of a whorl of three leaves, but 
where there are four complete cotyledons there are never more than 
two leaves — a very curious correlation. RP. Bb 
Chemical Analysis of the Plankton. — The chemical composition 
of the plankton of the Baltic Sea is discussed and compared with the 
analysis of certain agricultural products in a recent paper by Brandt.’ 
The Copepoda, Peridinidæ, and diatoms are the predominant forms 
in the plankton of this body of water. Fifty cubic centimeters of 
plankton of mixed constitution weigh, when dried, from 1.08 to 1.74 
‘grams; when diatoms predominate, the weight falls as low as .04 
gram ; and when Copepoda are abundant, it may rise as high as 2.1 
grams. The results of the enumerations made of the organisms in 
the different catches subjected to analysis are utilized in the computa- 
tion of their number in a gram of the dried plankton. It has thus 
been determined that it takes 675,000,000 diatoms (principally Chæ- 
toceros) Or 42,000,000 to 65,000,000 Peridinidz to weigh one gram; 
in the case of the marine Copepoda, from 300,000 to 500,000 are 
required ; while the single analysis of a fresh-water plankton composed 
mainly of the larger individuals indicates that 50,000 to 124,000 are 
1 Jones, H. L. tee ge Forms of Maple Seedlings. Oberlin College, Zabo- 
desig Bulletin (1898), No. 
2 Brandt, K. a a zur Kenntniss der chemischen Zusammensetzung des 
Planktons. Wissensch. Meeresuntersuchungen, Neue Folge, Bd. iii (1898), Heft 2, 
PP. 45-90. 
