BROOK, CREEK, AND RIVER 



283 



spines of segment nine are sharp, divergent, and longer than 

 the appendages of segment ten, it is a nymph of Tetragoneiiria; 

 while if the spines of nine are 

 incurved and not longer than 

 the appendages of ten, the 

 nymph is thsitoiSomatochlora. 

 If the fish of the streams 



are studied, again we find Fig. 431.— Rainbow darter, £//zeo,y/owa 



certain species in the head- coendemn, two-thirds natural size. 



waters, others coming in 

 down in the mid-course, still 

 others not appearing until the 

 river stage is reached, and 

 finally some largely confined 

 to the estuary. Streams that 

 are mere brooks, short and 

 small, will have the same sort 



of fish that are found near Fig. 432.— Head of common sucker, 



the headwaters of the larger C^^^stofmis commersonii, one-third natural 



size 



rivers. The horned dace 



(Fig. 427) is apparently the fish that works its way farthest 



upstream, often living in the pools of brooks that otherwise 



'Sfjf^aiaaa 



Fig. 433. — Stone roller, Campostoma anomalum 



have dried up. The red-bellied dace (Fig. 428) and the black- 

 nosed dace are not far behind it. The blunt-nosed minnow 

 (Fig. 429), Johnny darter (Fig. 430), and the rainbow darter 



