THE NAUTILUS. 



83 



Boulder and gravel bottom . . .20 acres 

 Sand bottom . . . . .85 acres 

 Clay bottom . . . . .92 acres 

 Mud bottom ..... 684 acres 



Total acreage .... 881 



Plant life is very abundant in the bay and it is due to the 

 great quantity of this life that the animal life is so abundant. 

 The submerged plants are the most abundant in species, Pota- 

 mogeton, Najas, Elodea, Vallisneria and Myriophyllum being the 

 principal genera represented. Scirpus, Pontederia, Nymph&a 

 and Castalia are the most abundant of the emergent types of 

 vegetation. The most surprising result of the plant analysis 

 has been the presence of great quantities of filamentous and 

 other algae, the former in places fairly choking the water. Up- 

 wards of 36 species were found in the material examined by Dr. 

 E. N. Transeau, including Cladophora, Oedogonium, Ulothrix 

 and Spirogyra among the filamentous species. It was in this 

 mass of algae, which often formed a thick blanket, that the 

 greater number of mollusks and other animals were found. 



In the list of species to follow, reference is made to the depth 

 of water and to the character of bottom upon which the species 

 was found. As all but a very few were collected in Lower 

 South Bay, the locations are given only where the species was 

 found in a habitat outside of this area. My thanks are due Dr. 

 H. A. Pilsbry, Dr. Bryant Walker, and Dr. V. Sterki for the 

 determination of critical material. To Dr. C. C. Adams and 

 Dr. Hugh P. Baker, of the New York State College of Forestry 

 I am indebted for the opportunity of making the studies from 

 which these notes are abstracted. 



Unionidae. 



Elliptic* complanatus ("Solander" Dillwyn). In Technical 

 Bulletin, IV, page 252, and in the Nautilus, XXX, page 8. 

 reference is made to the presence of Margaritana margaritifera 

 (L) in the lake. This should be eliminated from the lists as it 

 was founded upon pathologic individuals of Elliptio complanatus. 

 This Elliptio is the commonest mussel in the lake occurring on 



