255 



Here are totals of eleven species found in the Ohio basin against fifteen 

 which are found in the Wabash basin. The proportion would be substantially 

 the same if the synonymous forms included, printed in small capitals, were ex- 

 cluded from the list. None of the members of the genus Vivipara appear in the 

 Ohio basin, while but two Unione!< are found in the AVabash basin that are not 

 found in that of the Ohio. No limnteids appear to be characteristic of the Ohio 

 basin, while three such are found in the Wabash. Yet it is to be constantly 

 borne in mind that further collections may invalidate this comparison by the 

 discovery of other common forms, or that some of these forms may yet be ascer- 

 tained to be common to the two faunas. 



Turning again to the northern portion of the State, the most interesting fact 

 presented is the existence of a number of (^hio drainage forms in the Maumee 

 River, a stream of the Atlantic drainage. Opportunity was afibrded the past 

 spring to make a small collection in the Maumee and the St. Mary's Rivers at 

 Fort Wayne, well within the Maumee Basin. While the collection was by no 

 means exhaustive, it developed some very interesting facts which possess more 

 than a passing significance. 



Among the Ohio River forms found were the following : 

 Unio rubiginosus, Unio davits, 



Unio glans, Unio giBbosus, 



Unio Inteolus, Unio parvus, 



Unio retusus, Margaritana calceola, 



Margaritana complanata, Goniobasis pulchella, 



Anodonta edentula, Unio pressiis. 



These species are accredited to the Western fauna, and most of them are not 

 hitherto recorded as belonging to the Atlantic fauna. Two of these were so re- 

 corded by the writer as long ago as 1S77, in the Erie Canal, in the Mohawk drain- 

 age, at Mohawk, N. Y., and record made of the fact in the "American Natural- 

 ist," Vol. XII, pp. 472, 473. Other records have since appeared. Unio luteolus 

 is often quoted in faunal lists used for exchange purposes by Eastern collectors, 

 but in every case where specimens have been secured, thus far, they have proven 

 to be the male forms of the totally distinct Unio cai-iosus, a form not j'et found in 

 Western waters. Anodonta edentula may be, and probably is, a geographic variety 

 of the Eastern Anodonta undulala, but the Maumee forms are Western in facies. 

 It is therefore proper to regard it here as a Western shell in the drainage of an 

 Atlantic stream. So far as the specimens go which are in ray possession, they do 

 not present very marked differences from the same shells found a few miles to the 

 west in waters tributary to the Wabash. The environmental factors are precisely 



