96 NEW YORK STATE MUSEUM 
The Permic of Portugal has furnished the final straggler of the race 
in a small Eurypterus [de Lima, 189o]. 
D_ Bionomy of the eurypterid faunas 
A very interesting problem in the study of the eurypterids is that 
of their bionomic relations and geologic facies. A philosophic contri- 
bution to the discussion of this problem has been given by Professor 
Chamberlin in his paper On the Habitat of the Early Vertebrates [1900, 
Pp. 400]. 
Chamberlin’s hypothesis is to the effect that ‘the fish and the 
eurypterids descended from the rivers to the sea in the mid-Paleozoic, 
though their remote ancestors may have ascended from it,’ and the 
principal argument in its support is found in the claim that “ there is 
only one conspicuous type that is facilely suited to free life, independent of 
the bottom, in swift streams, and that is the fish form’’; it is further 
urged that ‘‘ this could have developed only in water that possesses a per- 
sistent and usually rather rapid motion in a fixed direction, 1. e., in 
rivers.”’ | 
In support of this hypothesis it is pointed out that the Paleozoic fish 
and the similarly built eurypterids are always associated and it 1s suggested 
that the two possessed a parallel development due to the same physical 
influence. This view of the fresh-water origin of the eurypterids is directly 
contradictory to the current view among paleontologists of their originally 
marine habitat and later adoption of first a brackish and finally a fresh- 
water life. Zittel-Eastman’s Textbook of Paleontology expresses this 
prevailing view as follows [1896, p. 673]: 
They are found associated with graptolites, cephalopods,.and trilobites 
in the Ordovician of Bohemia and North America; with marine Crustacea 
(Phyllocarids and Ostracods) in the Silurian; with Ostracoderms and Arth- 
rodires in the Devonian; and with land plants, scorpions, insects, fishes 
and fresh-water amphibians in the Productive Coal Measures. It is ap- 
parent, therefore, that from being originally marine forms, they became 
gradually adapted to brackish, and possibly even fresh-water conditions. 
