i8o College of Forestry 



of Milton and Fitzgerald Points. The specimens vary from a 

 narrow form somewhat resembling canadensis to the wide shell 

 of the typical form. This species is easily distinguished from 

 catascopium by the spermaciti-like color of its shell. The indi- 

 viduals collected in 191 7 were all alive. 



89. Galba palustris (Miiller). 



In IQT5 a single specimen of this species was observed in a 

 Typha habitat near the shore at Brewerton (Baker, '16, p. 286). 

 In 1 91 7 the true habitat of this species, in Oneida Lake, was 

 discovered, abundantly represented by individuals. The habi- 

 tat is a sandy beach, exposed to the action of the waves of the 

 lake. This is an unusual habitat for this species which is 

 usually found in swampy or marshy ponds or on shores well 

 protected from violent wave action. The individuals show the 

 effect of the environment, the shell being thick and solid and 

 the aperature wide and bell-shaped in the majority of indi- 

 viduals, indicating an effort to broaden the shell to provide a 

 better clinging power to resist the moving power of the waves. 

 The present habitat is comparatively new, dating from the 

 digging of the barge canal channel the debris of which was 

 deposited on the shore of the lake. If, as may have been the 

 case, the palustris occupied the old shallow area bordering 

 the shore, the survivors would be compelled to adapt them- 

 selves to the new environment after the old, swampy shores 

 had been obliterated. The condition of the shells, thick and 

 solid with flaring outer lip, indicates that they are adapting 

 themselves to a new environment, and the history outlined 

 above seems plausable. A few specimens were also dredged 

 some distance from the shore in water 5 feet deep near the 

 vegetation islands. None were collected in 1916. 



90. Galba obrussa (Say). 



A single dead individual of this species was found in a 

 dredging unit on a bar near the second lagoon east of the 

 steamboat landing at Lower South Bay, in one and a half 

 feet of water. It is young, 5 mm. long and had evidently 

 been washed into this habitat from some region along the 

 shore, which was not discovered in the time at our disposal. 

 With Galba humilis modicella, this species should be found 

 abundantly along the shor^ of marshy or quiet bodies of water. 



