1 68 College of Forestry 



concerninf^ the details of the breedhig habits of this group of 

 mollusks are desirable. This is the first record of this species 

 in Oneida Lake. 



Family Amnicolid.^ 

 Genus Gillia Stimpson 



50. Gillia altilis (Lea). 



Occurred on boulder, gravel, sand, and mud bottoms in one 

 to 14 feet of water. Half -grown and adult individuals were 

 abundant in some habitats. 



Genus Somato(;yrus Gill 



51. Somatogyrus subglobosus (Say). 



A few specimens were collected associated with Gillia. All 

 were immature. 



(ienus Bytiiinia Gray 



52. Bythinia tentaculata (Linn). 



This common species occurred abundantly in Lower South 

 Bay on gravel, sand, clay, and mud bottoms in water one to 14 

 feet deep. Most abundant on clay and mud bottoms in water 

 four to 14 feet deep. A large percentage of the individuals 

 collected were young or immature. Tentaculata is especially 

 abinidant among filamentous algae (mostly Cladophora fracta), 

 and a single specimen was collected from a leaf of Sagittaria 

 arifolia. A pint of algse, representing 100 square inches of 

 area on an old log in five feet of water, yielded 97 adults and 

 1,270 young individuals of this species. 



Genus Amnicola (iould and Haldeman 



53. Amnicola limosa (Say). 



A small form of this species occurs in the western part of 

 Oneida Lake (Baker, '16, p. 268). No specimens were ob- 

 tained with the 1916 collections. 



*54. Amnicola limosa porata (Say). 



This is the largest Amnicola in the lake, 5 mm. in length, 

 with a globose body whorl and a wide umbilicus. This race of 

 limosa was found only in three habitats; boulder bottom in one 



