170 CoUcf/e of Forestry 



*57. Amnicola clarkei Pilsbry. 



'Ihis small, very narrow, subacute species occurred m but 

 four habitats, on sand, clay, and mud bottoms, usually in alg^e, 

 in water 3-8J/2 feet deep. It was most abundant on a mud 

 bottom in 8j/j feet of water. 



"'58, Amnicola oneida Pilsbry. 



This narrowest of the Amnicolas in the lake was found on 

 all bottoms of the bay and at all depths from i^ to 15 feet. 

 It is not common on boulder and gravel bottoms, but on sand, 

 clay, and mud bottoms, where there is a covering of filamen- 

 tous algae (Clodophora, CEdogonium, Spirogyra, etc.) in 2J/2 

 to 4 feet of water, it is the commonest mollusk in the region. 

 Several hauls of the dredge on a mud bottom in water 8^-9 

 feet dee[) also disclosed this species in abundance, but it is not 

 common in the deeper water, none being found deeper than 15 

 feet, and at this depth it was very rare. Many young and 

 immature individuals were collected with the adult specimens. 



An elongated individual of Amnicola related to lustrica was 

 found in 191 5 which seemed dififerent from typical lustrica 

 and Dr. Pilsbry suggested that special search should be made 

 for additional material (Baker, '16, p. 269, fig. 45, no. 21). 

 This specimen was collected near Frenchman Island on a hard 

 sand bottom in three feet of water. The discovery of the 

 novelty in- large numbers was one of the interesting results of 

 the 1916 field work. Oneida was observed in the 1915 collec- 

 tions from the following habitats, mixed with lustrica. French- 

 man Island, Nos. 216-g, 217-n; Shepard Point, Nos. 225-e, 

 238-h; Deer Point, Big Bay, No. 234-e; Muskrat Bay, No. 

 247-a; Nicholson Bay, No. 262-a. 



59. Amnicola lustrica Pilsbry. 



This species was collected from but one habitat, a boulder 

 shoal north of Dunham Island in two feet of water. Typical 

 lustrica was collected near Frenchman Island in IQ15 and in 

 the western part of Oneida Lake. This species evidently does 

 not live in the small bays. 



