BEHAVIOR AGREEMENT AMONG ANIMALS. 



297 



FIGS. 9-16. General form of the pool animals. 9, Shiner (Notropis atherin- 

 oides Raf.); 10, River chub (Hybopsis kentuckiensis Raf.); n, Rock bass (Amblo- 

 plites rupestris Raf.) 12, Damsel fly nymph (Calopteryx maculata Beauv.) ; 13, River 

 snail (Campeloma subsolidum Ant.) 14, Burrowing dragon fly nymph (Macromia 

 sp.); 15, Mussel (Anodontoides ferussacianns Lea) 16, Small bivalve (Sphaerium 

 sp). The fishes were juvenile. All are drawn en the same scale. 



III. REACTIONS TO CURRENT. 



i. METHODS. 



The tests were made in an Allee Straight Current apparatus, 

 Fig. 17, the trough of which is II cm. wide, 7 cm. deep and 68 



FIG. 17. Alice's straight current apparatus. 



cm. long. Pieces of screen (32 meshes per inch) were placed 

 across each end adjacent to the round reservoirs. The screens 



