numbers of small particles composed of them were floating down 

 stream. Samples of sludge obtained at this time were full of slime 

 worms, as usual, those from the chute on the north side of the island 

 averaging a hundred per plate, and those from the south side twice 

 as many. In the north chute were also many living snails, especially 

 Canipelonia (which was very abundant) and a much smaller number 

 of Physa and Pleurocera. The sludge collections from the south 

 shore contained some Campeloma, but none of the other snails. In 

 the channel below the island the current was too swift to permit the 

 deposit of a fine sediment, and the bottom was sandy, with dead 

 snails only. The only blue-green algre were a Lyngbya and a Phor- 

 midium, taken in three collections, while filamentous green algae oc- 

 curred in thirty-seven. The most abundant forms were Cladophora, 

 both crispata and glomerata, and Stigeodoninin tcuiie and lubriciim. 

 Living sponges were obtained on dead mussel shells in three col- 

 lections. 



The isopod Ascllits was common in dredge hauls and among the 

 algae at the edge. Crawfishes were taken here in two collections, 

 and Chirono}}ius larvae and pupae in seventeen. The situation was not 

 productive of Unios, and but two species were taken alive — Quadnda 

 plicata and Symphynota coiiiplanata. Five collections contained both 

 dead and living SpJicrriiDii transversuui, and four contained living 

 Ancyiiis. Statoblasts of Plitniatella were abundant in the drift, and 

 other Bryozoa were common on shells of dead and living mussels. 



Our fishing at this point was mainly done September 3, between 

 Starved Rock and the mouth of the Vermilion. A quarter of a 

 mile below the landing, on the north shore, at the mouth of a creek, 

 a dynamite explosion gave us a blunt-nosed minnow, many shiners, 

 a Notropis jejumis, a large-mouthed black bass, and a gizzard-shad. 

 A half-mile below, dynamite and a 60-foot seine yielded a very large 

 number of shiners, three silverfins, a golden shiner, and a short- 

 headed red-horse (Moxostoma breznceps). A haul of the 60-foot 

 seine on "Little Rock bar" near the south shore brought in several 

 hundred young carp from two to five inches long, a great abundance 

 of shiners, and a black bullhead. A haul in the channel with a 

 200-yard seine with an inch mesh, on the other hand, brought in no 

 fish. A dynamite explosion near the south shore, three quarters of 

 a mile above the mouth of the Vermilion, brought to the surface 

 three 2-pound carp and many shiners. Additional dynamite explo- 

 sions made September 3 and 4 at five different points down the river 

 as far as Spring Valley, gave us large numbers of the shiner 

 (Notropis atherinoides), but no other specimens except a 3-inch carp 

 and four golden shiners. 



