McAtee and Weed — Fishes of Vicinity of Plummers Island, Md. 5 



Leticiscus vandoisidus) were able to reach the upper part of the 

 stream than was the case in Dead Run. There is little proba- 

 bility that there has been any meddling by mankind with the 

 fish fauna of these two streams. 



Rock Run, Md. 



Rock Run has its source near Potomac, and after a course of 

 about 5 miles, no part of which is precipitous, empties into the 

 Potomac just below Lock 11 of the Chesapeake and Ohio Canal. 

 This run flows under the canal through a large culvert. Here 

 the stream is shallow and of comparatively uniform depth ; it 

 flows from the culvert in a thin sheet and drops about 18 inches 

 into a deep pool. In time of flood river water backs into this 

 culvert; nevertheless large fishes running in from the river do 

 not as a rule go above this pool. Scores of Catostomus and 

 Moxostoma are netted here every spring. The culvert marks 

 very well the boundary between the true creek fauna and the 

 intruders from the river. 



The following have been taken only in or above the culvert: 



Semotilus atromaculatus Rhinichthys cataractae 



Leuciscus vandoisulus Boleosoma olmstedi 



Notropis cornutus Etheostoma flabellare 



The following species have been taken only below the culvert: 



Moxostoma macrolepidotum Chaenobryttus gulosus 

 Anguilla rostrata Lepomis cyanellus 



Ambloplites rupestris " gibbosus 



The following species have been taken both above and below the 

 culvert: 



Schilbeodes insignis Rhinichthys atronasus 



Catostomus commersonii Exoglossum maxillingua 



Hypentelium nigricans Lepomis auritus (only one small 



Pimephales notatus specimen taken in culvert. 



Notropis amoenus Probably accidental ; this fish 



hudsonius clearly belonging to the deeper 



water fauna) 



Cabin John Run, Md. 

 Cabin John Run rises near Rockville, and has a total course of 

 about 7i miles. It also flows through a culvert under the canal, 

 and it is at this point that most of the following species were 

 collected : 



