517 



them black bnllheads (Ameiunts inclas), one a rock bass {Amblopli- 

 tes rupcstris), and one a blue-gill siinfish {Lcpomis pallidus). These 

 were all taken in set-nets in the less polluted water of the southern 

 or Kankakee side of the river — the bullheads near the outlet of Mazon 

 slough, and the rock bass and sunfish about seventy-five yards above. 

 They were the entire product of a haul of the 200-yard seine, made 

 on the north shore August 2 ; five settings of the trammel-net on 

 the south side of the river; continuous fishing with three and four 

 set-nets August 2 to' 9; fifteen hauls with small seines made on both 

 shores, September 25; and the explosion of twenty half-pound 

 sticks of dynamite, August 2 to 9, near both shores and in the middle 

 of the stream. The river here was, in fact, practically destitute of 

 fishes, and the few taken were in close proximity to the INIazon 

 slough. Moreover, some of the bullheads were "fungused" or in 

 otherwise unwholesome condition. 



The only other vertebrates taken here were a single frog, two 

 snapping turtles, and a soft-shelled turtle. The search for mollusks 

 yielded seven species of mussels, all the specimens dead, however, 

 except for one collection made in Mazon slough. Snails were ob- 

 tained several times^ — Caiupcloma, Goniohasis, and Pleuroccra all 

 dead, but Planorhis, Physa, and Lynincca alive in part, six collections 

 containing living specimefis of these genera and nine collections 

 containing dead. No Sphccrium or Pisidium were taken here, nor any 

 Bryozoa, sponges, or hydroids. 



Numerous samples of sludge from the bottom were spread in thin 

 layers on plates, and left for the animals to emerge, with the result 

 that tubificid worms appeared in numbers varying from 12 to 200 

 per plate. These were most abundant in samples taken nearest the 

 shores. There were no leeches or planarians in our collections, but 

 four of them contained naiid worms {Dcro furcata). A single 

 crawfish was taken in Mazon slough, and bleached, unwholesome- 

 looking specimens of an amphipod crustacean {Hyalclla knicker- 

 bockeri) were present in the duckweed along the south bank. Sev- 

 eral species of water-beetles and water-bugs were found along both 

 shores, but, with the exception of larvje and pupfe of Chironouius, 

 these were all adults which take their oxygen from the air and not 

 from the water. There was some pondweed (Pontcderia) and duck- 

 weed (Lcmna and Wolff ia) along the banks. 



No later collections were made at Morris in 191 2, but we have 

 additional oxygen determinations for November 2 and November 

 14. The following table gives these data for the midstream and the 

 two shores on these two dates. 



