THE NAUTILUS. 



Vol. XXXIII JANUARY, 192O. No. 3. 



GORIOBASES Of OHIO. 



BY CALVIN GOODRICH. 



Some months ago I had occasion to map the known distribu- 

 tion of Goniobasis livescens Menke and G. semicarinata Sav within 



V 



the borders of Ohio. This distribution is somewhat peculiar. 



Beginning on the western gide of the state above the central 

 line we find that livescens is the Goniobasis of the Maumee river 

 system and of the shallows of Lake Erie as far as Sandusky 

 Bay, where G. haldemanni occurs in company with livescens in 

 the drift of the beaches. So far as exploration thence east 

 shows, livescens appears alone to the northeastern corner of 

 Ohio. It is the species of Sandusky River, flowing into San- 

 dusky Bay, of Rocky and Cuyahoga Rivers which enter the 

 lake at Cleveland, and of Conneaut Creek near the eastern 

 border. Below the divide between the lakes and the Ohio River 

 drainages, I found livescens in Beaver Creek, a tributary of the 

 Wabash. There is then a great gap in its occurrence until the 

 Hocking River is reached, east of a north and south central line 

 drawn through the state. Just east of this, again, livescens has 

 been collected in the Tuscarawas River of the Muskingum sys- 

 tem by Dr. Sterki, and in at least one of the Tuscarawas 

 branches. The G. gracilor Anth. of the Summit county lakes 

 is plainly an offshoot of livescens, as indicated by connecting 

 forms taken in this same region. 



Goniobasis semicarinata, less variable and more easily recog- 

 nizable even in the field than livescens, is the species of the 

 Great Miami, Little Miami and the Scioto Rivers, all in the 



