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the crinoids would creep along the shore lines in the direction 
of the prevailing currents or winds, being everywhere confined to 
a narrow belt owing to the inability of the. young which fell into 
deep water to develop. The species of the deeper water, being 
free from the action of the winds and being subject to very slight 
if any currents, would gradually as the depth increased, form a 
more rounded, and finally, at great depths a circular dispersal figure, 
with the parent near or at the center instead of at one end. Their 
young would form similar circular dispersal figures, the centers 
of these circles being on the periphery of the original circle; and 
thus the crinoids of the deeper water would spread out in all 
directions at an equal rate, and would spread over an enormous 
area in a comparatively short time; in other words, while the littoral 
crinoids are capable, from the nature of their habitat and sur- 
roundings, of linear distribution only, the crinoids of the deeps 
can undergo radial dispersion, which carries them over a far greater 
extent of territory, though more slowly, for a current strong enough 
to cause the formation of a lineal or fan-shaped dispersal figure 
must carry the larvæ much further than they would, with their 
very feeble powers of locomotion, swim of themselves. In the inter- 
mediate depths of course all intergradations between a linear or nar- 
rowly fan-shaped and circular dispersal figure would be found, with 
a corresponding distribution of the intermediate forms. 
The littoral Indo-Pacific-Japanese faunal area has as its center 
of intensity a triangle whose apices are roughly Luzon, Borneo, 
and New-Guinea. The Oceanic area is of universal extent in the 
deeper waters. Between the two extremes we. may trace with 
more or less distinctness an Intermediate area whose maximum 
intensity is within a triangle which may be considered as embra- 
cing the region between the Kermadec Islands (near New Zealand), 
Singapore, and Japan. This Intermediate area is confined to the 
Indian and Pacific Oceans. Characterized mainly by genera of 
Thalassometridæ with a few of Antedonidæ, it has the same general 
