No. 715]    RACIAL AND INDIVIDUAL VARIATION                    123 
Interest is growing in the correlation between the 
variations exhibited by fishes and the physico-chemical 
environment in which they develop: witness such papers 
as these: d'Ancona (1927), Johansen (1928), Schnaken- 
beck (1931), Mottley (1931) and Parr (1932). Signs are 
not lacking that the study of variation in fishes and other 
animals is being rejuvenated into a live division of zool- 
ogy. This study may well assume such a position, if it is 
prosecuted not as an end in itself, but as a tool to be used 
in solving problems in systematics, economic zoology, 
zoogeography and evolution. 
LITERATURE CITED 
Adams, Chas. C. 
1915. "The Variations and Ecological Distribution of the Snails of 
the Genus Io," Mem. Nat. Acad. Sci., 12, 2nd Mem.: 1-184, 
fig. 1, pls. 1-61. 
Allen, J. A. 
1871. "Mammals and Winter Birds of East Florida," Bull. Mus. 
Comp. Zool., 2, No. 3. 
1874a. "Laws of Geographical Variation in North American Mammals 
and Birds," Am. NAT., 8: 227-229. 
1874b. "Geographical Variation in North American Birds," AM. NAT.,

8: 534-541 (also in Proc. Bost. Soc. Nat. Hist., 15, 212-219). 
1876. "Geographical Variation among North American Mammals, 
Especially in Respect to Size," AM. NAT., 10: 625-627 (also 
in Bull. Geol. and Geog. Surv. Terr., 2: 309-344.) 
1877. "The Influence of Physical Conditions in the Genesis of Spe- 
cies,'' Radical Review, 1: 108-140 (reprinted in Ann. Rept. 
Smith. Inst. for 1905: 375-401). 
Ball, Gordon H. 
1922. "Variation in Fresh-water Mussels," Ecology, 3: 93-121, figs.

1-6. 
Boycott, A. E. 
1928. ''Conchometry," Proc. Malacol. Soc., 18: 8-31. 
Chabanaud, Paul 
1929. ''Observations sur la taxonomie, la morphologie et la bionomie 
des Sol6ids du genre Pegusa," Ann. Inst. Oceanogr., 7 (6): 
215-261, figs. 1-38, pis. 1-2. 
Chapman, Frank M. 
1926. "Distribution of Bird Life in Ecuador," Bull. Am. Mus. Nat.

Hist., 55. 
Colton, Harold Sellers 
1916. "On Some Varieties of Thais lapillus in the Mount Desert Sec-

tion, a Study of Individual Ecology," Proc. Acad. Nat. Sci. 
Phila., 1916: 440-454, figs. 1-4.