9 
72 Variation in Chilomonas 
4. The distribixtion of variation is skew in the case of the individuals from 
the optimum cultural condition, and symmetrical in the case of the other group. 
5. The skewness is positive, or in other words, the majority of the population 
are larger than the modal individuals. 
6. There is a considerable degree of correlation between length and breadth 
of body in Ghilovionas (coefficients > '6). The regressions between these 
characters are linear. 
7. The values for the coefficients of variation and correlation in Chilomonas 
are of the same general order of magnitude as those which have been determined 
for other Protozoa. 
8. There is a distinct correlation between the shape of the body and its 
absolute size in Chilomonas. The bearing of this result on Driesch's first "proof 
of the " Autonomie der Lebensvoi'gange " is discussed. 
LITERATURE CITED. 
BuTSCHLi, 0., 1878. Beitrage zur Kenntniss der Flagellaten und verw. Organismen. Zeitsch. 
f. wiss. Zool. Bd. XXX, pp. 205—281. Taf. xi— xv, 1878. 
, 1883 — 1887. Protozoa. Bronns Klassen und Ordnungen des Thier-Reichs. 
Bd. I, II Abth. 
DiMON, A. C, 1902. Quantitative Study of the Effect of the Environment upon the Forms of 
Nassa ohsoleta and Nassa trioittata from Cold Spring Harbor, Long Lsland. BiometriJca, 
Vol. II, pp. 24—43, 1902. 
Driesch, H., 1900. Die isolirten Blastoraeren des Echinidenkeimes. Eine Nachpriifung und 
Erweiterung friiherer Untersuchungen. Arch. f. Entivickelungsmech. Bd. x, pp. 361 — 410, 
1900. 
1901. Die Organischen Regulationen. Vorbereitungen zu einer Theorie des 
Lebens. Leipzig (Engelmann), 1901, pp. xv and 228. 
Fawcett, G. D., 1902. A Second Study of the Variation and Correlation of the Human Skull, 
with Special Reference to the Naqada Crania. Biometriica, Vol. i, pp. 108 — 467, 1902. 
Macdonell, W. R., 1904. A Study of the Variation and Correlation of the Human Skull, with 
Special Reference to English Crania. Biometrika, Vol. in, pp. 191 — 244, PL i — L, 1904. 
Pearl, R., 1903. Worcester's Formol-Sublimate Killing Fluid. Jour, of Applied Microscopy, 
Vol. VI, p. 2451. 
, 1906. A Biometrical Study of Conjugation in Paramecium. In press. (Abstract) 
R. S. Proc. Vol. Lxxvii, pp. 377—383. 
and Dunbar, F. J., 1903. Variation and Correlation in Arcella. Biometrika, Vol. ii, 
pp. 321—337, 190.3. 
, 1905. Some Results of a Study of Variation in Paramecium. 
Preliminary Communication. Seventh Report Mich. Acad. Sci. 1905. 
Pearson, K., 1897. Mathematical Contributions to the Theory of Evolution. On a Form 
of Spurious Correlation which may arise when Indices are used in the Measurement of 
Organs. R. S. Proc. Vol. lx, pp. 489—498, 1897. 
, 1905. "Das Fehlergesetz und .seine Verallgemeinerungen durch Fechner und 
Pearson." A Rejoinder. Biometrika, Vol. iv, pp. 169—219, 1905. 
Warren, E., 1902. Variation and Inheritance in the Partheuogenetic Generations of the Aphis 
"Hyaloptorus trirhodus" (Walker). Biometrika, Vol. i, pp. 129—154, 1902. 
