The Productivity of Fish Food in Oneida Lake 177 



fairly common on a boulder bottom, two to four individuals 

 being found on each boulder. Associated with the algse Clado- 

 phora fracta and CEdogoniujii. 



Genus Segmentina Fleming 



*82. Segmentina armigera (Say). 



This species, here first recorded from the lake, was collected 

 in two habitats, one a swampy shore in Short Point Bay among 

 the alga ddogoniiim and the other in a protected bay on the 

 north side of Frenchman Island on leaves of Sagittaria arifolia. 

 Both habitats are in shallow water with mud bottoms. The 

 individuals of armigera are rather small. 



Family Lymn^id^e 



Genus Lymn^a Lamarck 



83. Lymnaea stagnalis lillianae Baker. 



This, the largest of the gastropods in the lake, was found 

 only at one habitat, the rocky shore of the lake east of Norcross 

 Point, in water a few inches to two feet in depth. All were 

 immature, half, or three-quarters grown. A single young dead 

 shell 14 mm. in length was found in a small bay on the south 

 shore of Long Point in water three and a half feet deep, but 

 it had evidently been brought there from some other habitat. 



In September, 191 5, egg capsules of this Lymncea were 

 observed on the leaves of Nyniphcua and Castalia, dead Typha 

 leaves, the floating leaves of Potamogeton natans, and on 

 bottom debris, and it is singular that no young individuals were 

 observed in July, 1916 (except the dead one before men- 

 tioned) . Data are not at hand bearing upon the time of hatch- 

 ing of the eggs laid in the fall. No young were noted in the 

 fall of 1915. When do these eggs hatch, in the fall or in 

 the early spring of the following year? Aquarium experiments 

 on a large scale are necessary to provide information on these 

 points. It seems evident that the young liliancc pass their early 

 days in deeper water, perhaps among vegetation, and later, 

 when almost half grown, migrate to the bouldery shores. This 

 opinion is based on the observation that the species w'as not 



