246 Wisconsin Academy of Sciences, Arts, and Letters , 
Table III. The Distribution of the Plankton Organisms. 
The verticle distribution of the various organisms is shown by giving the number 
of individuals per cubic meter of water in the different strata. The members grouped 
in the different columns are indicated as follows: 
1. Cladocera, D. h .=Daphnia hyalina, D. p ,=Dapbtnia pulex, C.—Ceriodaphnia, 
B.=Bosmina, Bi.— Diaphanosoma, P.=Polypiiemus , Ch =Chydorus. 2. Copepods, 
I>.=Diaptomus, Li.=Limnocalanus, G.=Cy clops, N .=Nauplii. 3. Rotifera, A. a.= 
Anuraea aculeata, A. c .—Anuraea cochlearis, A. s.=Anuraea stipitata, N .=Notholca, 
S.=Synchaeta, P .=Polyarthra, Vl.—Ploesoma, A. =Asplanehna, C .=ConocUilus, Tr.= 
Triartlira, P e.=Pedalion fennicum, R .=Rattulus, Bd =Bdelloid rotifer , B. p.= 
Brachionus pala. 4. Protozoa, C .—Ceratium, D ,—Dinobryon, P =Peridinium, M.= 
Mallomonas, T.=Tintinnus, V.=Vorticella. 5. Algae exclusive of diatoms, C.=Clath- 
rocystis, Aph.= Aphanizomenon, A=Anabaena, G.=Gloeocystis, G1 .=Gloeocapsa t 
Cl .=Closterium, S.~Staurastrum, Z.=Zygnema. 6. Diatoms, A.=Asterionella, C.= 
Cyclotella, F .=Fragilaria, M.=Melosira, S.=Synedra, T =Tabellaria. 
Lake Amatitlan, February 5, 1910. 
Depth, 
meters 
Cladocera 
Copepoda 
Rotifera 
Protozoa 
Algae 
exclusive 
of diatoms. 
Diatoms 
0-5 
D.h. 
14,400 
D. 
11,600 
A. s. 
300 
C. 
1,131,500 
201,500 
G. 
15,500 
F. 15,500 
C. 
5,200 
C. 
11,400 
P. 
Cl. 
403,000 
M. 10,974,000 
B. 
4,200 
N. 
49,000 
s. 
77,500 
S. 93,000 
A. 
15,500 
C. 
124,000 
5-10 
D. h. 
2,100 
D. 
5,100 
A. s. 
200 
c. 
503,100 
s. 
15,500 
F. 10,200 
C. 
900 
C. 
3,500 
p. 
15,500 
A. 
23,200 
M. 9,466,000 
Ch. 
25 
N. 
9,400 
C. 
92,900 
S. 247,700 
B. 
500 
10-15 
D. h. 
100 
D. 
2,200 
A. s. 
100 
c. 
139,500 
s. 
15,500 
F. 15,000 
C. 
300 
C. 
4,200 
Pe. 
100 
p. 
12,500 
A. 
15,500 
M. 7,486,000 
B. 
500 
N. 
5,900 
C. 
62,000 
S. 620,000 
15-20 
D. h. 
200 
D. 
1,200 
A. s. 
100 
c. 
23,200 
s. 
46,400 
F. 23,200 
C. 
100 
C. 
5,600 
Pe. 
800 
p. 
23,200 
c. 
69,600 
M. 5,429,000 
B. 
100 
N. 
4,300 
Tr. 
100 
S. 719,200 
20-25 
D. h. 
400 
D. 
1,100 
A. s. 
100 
c. 
23,200 
c. 
54,200 
M. 4,497,000 
C. 
300 
C. 
4,300 
Pe. 
1,600 
p. 
31,000 
S. 294,000 
N. 
8,400 
25-33 
D. h. 
300 
D. 
900 
A. s. 
300 
c. 
■ 29,000 
s. 
14,500 
M. 5,118,000 
C. 
70 
C. 
6,600 
Pe. 
900 
p. 
43,500 
c. 
145,000 
S. 275,500 
N. 
6,300 
