VIL—THE DISTRIBUTION OF SPECIES 
FOOT-NOTES TO EVOLUTION. 
chromosome. The ultimate vital units. Significance of 
reduction. Reduction in Ascaris. Reduction in Crusta- 
cea, The chromatin as the bearer of hereditary influence. 
Indirect evidence. Direct experimental evidence. 
Illustrations not arguments. Cumulative evidence. 
The fauna of the Galapagos. Island life. Effects of mi- 
gration on species. Effects of isolation. Barriers to diffu- 
sion. Holarctic realm. Neotropical realm. Ethiopian 
realm. Indianrealm, Australian realm. Anomalies in 
distribution. Adaptation of animals to environment. 
Invasion of the Australian realm. Trout in Yellowstone 
Park, Two-Ocean Pass. Laws of distribution of ani- 
mals. Barriers of land, sea, and climate. Interdepend- 
ence of species. The arctic birch. Crossing the bar- 
riers. The flying fish. Subspecies or geographical 
variations. Doubtful species. Darwin’s experience. 
The shore larks. Work of Dr. J. A. Allen. Species de- 
fined by missing links. Analogy between variations of 
species and of words. A fauna like a language. The 
survival of the existing. How species change with time. 
Physiological isolation. 
VIII.—LATITUDE AND VERTEBRE 
Northern fishes have most vertebrae. Fewest vertebre 
in shore fishes of the tropics. Fewer vertebre indicates 
greater specialization. Analogy of tropical waters to 
cities of men. Origin of eels. Coral reefs the centre of 
fish competition. Cephalization through competition. 
IX.—EVOLUTION OF FOSSIL CEPHALOPODA. By Pro- 
fessor James Perrin Smith 
Introduction: General evidence of paleontology; in- 
completeness of the record. Law of acceleration of de- 
velopment. Nomenclature of stages of growth. Paleon- 
togeny: General statement; Brachiopoda; Crustacea; 
Mollusca; Pelecypoda; Cephalopoda; Method of work- 
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