Methods of Counting and Computing the Crustacea. 433 
kind. This quantity was found by experience to be the most ad¬ 
vantageous, since a greater number of animals was likely to cause 
confusion and fatigue in counting, and a smaller number led to 
loss of time. The trough thus filled was slowly moved through 
STATION (Pc(3/U& Ptfitt?/' m 
DATE CLug. /. /fft/- HOUR I'n m | 
SKY CXlCA/ls WIND TEiVSP. 
DEPTH 0-2 m. TOTAL DEPTH / % m. 
CATCH DILUTED TO ccm. ^ 
Ccm. COUNTED . FACTOR 6 
. ^ 
Counted 
-"V 
Total 
DIAPTOMUS I3.& 
2.^2. 
/m 
CYCLOPS . fit (f 2L- 
/bo 
/oto 
DAPHNIA PULEX, var. PULICARIA 0 i 
? o 
— 
D. HYALINA . %. (j 
n 
/oz. 
DAPHNELLA BRACHYURA 
<? 
su. 
LEPTODORA HYALINA 
2_/ 
CHYDORUS SPHAERICUS 
—. 
— 
CORETHRA LARVAE 
/(> 
CHIRONOIVIUS LARVAE . 
/ 
Fig. 1 . —Specimen Registry Card. 
the field of the microscope,, one species was counted at a time, 
and the number noted. When the entire quantity had been 
counted the results were footed up and compared. In general 
each of the countings showed closely corresponding results. The 
