12 Proceedings of the Biological Society of Washington. 



in the canal (December 14, 1913). The largest individual was 103-^ 

 inches long over all. 



Clupeid^. 



Alosa sapidissima (Wilson). — Shad. Ascends the Potomac to Great 

 Falls, hence is transient in our waters. Shad are still caught in dip nets 

 both at Great and Little Falls ; formerly some fishing of this nature was 

 done at Stubblefield Falls. 



Salmonid^. 



Salvelinus fontinalis (Mitchill). — Brook trout. In 1899 Smith and 

 Bean published the following remarks about the brook trout: " In former 

 years this fish inhabited Difficult Run, on the Virginia side of the 

 Potomac, below Great Falls, but was supposed to have been long since 

 exterminated. Recently, however, a few have been taken in this stream." 

 (P. 184). 



ESOCIDJE. 



Esox reticulatus (Le Sueur). Pike. Trout. Of occasional occur- 

 rence in the canal. 



Percopsid^. 



Percopsis omiscomaycus ("Walbaum). — Smith and Bean (p. 185) 

 state that this species has been taken in Cabin John Run. 



Centrarchid^. 



Pomoxis sparoides (Lacepfede). 



Pomoxis annularis Rafinesque. — These two introduced species are 

 indiscriminately referred to as Crappie. They are about equally common 

 and occur both in the river and canal. A specimen of annularis caught 

 May 19, 1907, measured 133=^ inches over all. 



Ambloplites rupestris (Rafinesque). — Goggle-eye. Introduced, has 

 been collected in Rock Run and in the canal. 



Chaenobryttus gulosus (Cuvier and Valenciennes). Introduced, has 

 been taken in Plummers Island channel, in Rock Run and the canal. 

 A specimen caught in Rock Run, April 7, 1912, has in many ways the 

 appearance of a hybrid. It has the shape of head, dentition, scaling and 

 fin count of Chaenobryttus and the color and body form of Lepomis 

 cyaneUus. An apparent hybrid with Lepomis gibbosus was taken in a 

 pool near Difficult Run, June 11, 1911. 



Lepomis cyanellus (Rafinesque). — Introduced and fairly common. 

 Has been taken in Plummers Island channel, in Rock Run and the 

 canal. Occurs also in some of the pools near Difficult Run. 



Lepomis auritus (Linnaeus). — Bream, Brim. Abundant in the river, 

 canal and the mouths of creeks. Several nests of this species were 

 observed in Plummers Island channel during the latter half of June, 

 1908. They were guarded by the males but were finally abandoned as 

 the water lowered before hatching occurred. The stomachs of specimens 



