300 AQUATIC CLIMAX COMMUNITIES 



equivalents in the river carp and buffalo fishes, which are similar in 

 exhibiting the sucking habit (cf. Ellis, 1931). 



The small-river climax occupies the long deep pools in streams 

 with a drainage area of 100 to 250 square kilometers, a width of 

 15-25 meters, and a depth of 1-23 meters; the bottom is of mud, and 

 the water is sometimes turbid, with trees and bushes usually lining 

 the bank. The rooted aquatic vegetation is wanting, but floating 

 duckweeds and blue-green and other algae occur in late summer (cf. 

 Leathers, 1923). 



Dominants and Subdominants. The dominants are fishes, which 

 are here arranged in accordance with their general importance: 



Permanent Residents 



Carpiodes difjormis Cope Blunt-nosed river cai-p 



Carpiodes velifer Raf. Quill back 



Ictalurus punctatus Raf. Channel catfish 



Aplodinotus grunniens Raf. Drum or sheepshead 



Dorosoma cepedianura (Le S.) Gizzard shad 



Ameiums melas (Raf.) Black bullhead 

 Megastomatobus cyprinclla (Ictiobus) 



(C. & V.) Red-mouthed buffalo 



Erogala (Notropis) whipplii (Gir.) Steel-colored minnow 

 Hyborhynchus {PimephalcH) notatus 



(Raf.) Blunt-nosed minnow 



Migratory Species 



Moxostoma aureolum (Le S.) Red horse (breeds in swifter water) 



Moxostoma brcviceps (Cope) Short-headed red horse (breeds in 



swifter water) 

 Catostomus commersonii (Lac.) Black sucker (breeds in small trib- 



utaries) 



Subdominants 



Hexagenia {bilineata, etc.) nymphs Burrowing mayfly nymphs 

 Chironomus plumosus (Larvae and other 



species of Chironomidae) Bloodworm 



Limnodrilus sp. Worm 



Secondary Species 



MuscuKum transvcrsum (Say) Finger-nail shells 



Sphncrium striatinum (Lam.) Finger-nail shells 



Pisidium sp. Finger-nail shells 



Anodonta grandis (SajO Mussel 



Proptera alata (Say) Mussel 



Lasmigonia complanata (Bar.) Mussel 



Campeloma Snail 



