THE DESTRUCTION OF THE FRESH-WATER FAUNA 

 IN WESTERN PENNSYLVANIA. 



(Plate VI.) 



By dr. a. E. ORTMANN. 



(Read April 23, 1909.) 



It is generally known that the advance of civilization in a coun- 

 try is connected with a retreat and the disappearance of the indige- 

 nous fauna. This has been observed most distinctly in those parts 

 of the world which have been settled by the white man in more 

 recent times, and in many cases we have positive records with ref- 

 erence to the killing and crowding out of the original inhabitants of 

 the country, belonging to the animal kingdom; yet these records 

 chiefly concern the more highly developed forms of life (mammals 

 or vertebrates in general), which preeminently attract attention. 



But there are many other forms of animal life, chiefly among the 

 invertebrates, which suffer the same fate. Such cases generally are 

 not noticed, but students particularly interested in such groups often 

 have reason to deplore the disappearance of interesting creatures, 

 which used to be abundant. 



The present writer, in connection with his duties as curator of 

 invertebrate zoology at the Carnegie Museum, has made it one of 

 his chief objects to study and to preserve records of the fresh- water 

 fauna of the northeastern section of the United States, and first of 

 all, of the country lying in the immediate vicinity of Pittsburgh. 

 This region belongs to the drainage of the upper Ohio and of Lake 

 Erie, and it is well known that originally a very rich fauna was 

 present here, a fauna which forms part of the great fauna of the 

 interior basin, eminently rich in all forms of fresh-water life. It 

 is also a well-known fact that on account of the progress of civiliza- 

 tion in western Pennsylvania, on account of its industrial and com- 

 mercial development, and all the various features of " improve- 



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