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facies as the Oceanic with which it intergrades, but is quite distinct 
from the Indo-Pacific-Japanese. 
The Indo-Pacific-Japanese littoral area has a definite and 
rather small center, .from which in all directions it rapidly dimi- 
nishes in intensity; yet one would think that, being subject to 
lineal dispersal, the species would spread rapidly in all direetions. 
To the northward many of them range to southern Japan, where 
the coldness of the water beyond undoubtedly checks any further 
advance; to the eastward the wide expanse of ocean between the 
islands is "an effectual barrier, for the time which would be 
necessary for the larvæ to cross these stretches of open sea is pro- 
bably greater than the length of the free-swimming stage; thus the 
larvæ could not get across, for before traversing the necessary 
distance they would develop and drop to the bottom.  Moreover, 
most of the islands are low and dry, and could not support a 
littoral crinoid fauna. The continous coast line of Australia has 
allowed the East Indian forms to creep all around that continent, 
though apparently the conditions in the south are too rigorous for 
many of them. Westward the great volume of fresh water thrown 
into the sea by the Ganges and Brahmaputra rivers marks the 
farthest limit of many genera and species; in fact, from that point 
Onward the fauna takes on quite a different aspect which is 
again changed by the desert Arabian coast, after which, down 
the east African coast, the fauna becomes very meager. 
The littoral comatulids appear to have reached the southern 
Point of South America by creeping eastward from the extreme 
south of the Indian Ocean; finding a continuous coastline and no 
large rivers or other barriers, they spread northward, keeping 
within a narrow thermal altitude, to the Bering Sea, thence south 
again to southern Japan, meeting the species which had invaded 
southern Japan from the south, though confined to colder water 
than the latter 2), 
Sy me: Carpenter and Dr. Hartlaub have mentioned a characteristic 
t Indian comatulid, Comanthus rotalaria (,Actinometra parvi- 
