664 
DAVID H. TENNENT 
of an investigator in this field, a full account of the fluctuating 
variation. 
In the text I shall refer only to points of a somewhat general 
interest which are brought out by the examination of the results. 
I take only the right anal arm measurement, z.e., the measurement 
from the posterior end of the body to the tip of the right anal arm. 
Series I. The mean, 14.11, is the lowest of an}^ of the series 
at this age. A diminution in length down through the 4th day 
is seen. On the 5th day there is an increase. The variation in- 
creases through the 4th day and is less on the 5th. Variation in 
correlation; oral arms on 3d and 4th day longer than anal arms. 
Series II. Right anal mean 2d day 14.86. Steady increase 
during the period studied. 14.86, 17.79, 20.16, 22.54. 
Variation: great; rises and falls. Many perfect forms. 
Series III. Right anal mean 2d day 16.76. Little change until 
the 5th day when a noticeable increase began. 16.76, 16.55, 16.96, 
20.16. 
Variation : high. Highest on the 5th day. Many perfect forms. 
Series IV. Right anal mean 2d day 1 5.86. Steady diminution 
through each day 15.86, 15.62, 13.65, 12.33. 
Variation: relatively low and consistently uniform. A weak 
series. 
Series V. Right anal mean 2d day 17.26. Increase to 4th day; 
then diminution, then increase, 17.26, 17.57, 16.50, 18.07. 
Variation : a gradual lessening. 
Series VI. Right anal mean, 3d day, 23.18. Slight increase on 
the 4th day, decrease on the 5th day. 23.18, 23.48, 23.00. 
Variation increases with age; highest on the 5th day; many large 
individuals. 
Series VII. Right anal mean, 4th day, 26.88. Variation high. 
Series VIII. Right anal mean, 6th day, 23.12. Variation 
relatively high. 
Series IX. Right anal mean, 6th day, 28.81. Variation rela- 
tively high. 
For the combined series I-V, the mean for each group of 500 
individuals of the same age was determined and the other con- 
stants calculated from these. 
