362 MEMOIRS OF THE CARNEGIE MUSEUM. 



EXPLANATION OF PLATE X. 



All figures are three-fourths natural size, a, lateral view; b, dorsal view. 



Fig. 1. Anodonta grandis Say. Normal creek-form, from Crooked Creek, Creek- 

 side, Indiana Co., Pennsylvania, collected May 27, 1908; C. M. Cat. No. 6L3649. 



Fig. 2. Anodonta grandis Say. Gravid female of the pond-form gigantea (Lea), 

 from pond at Harmarville, Allegheny Co., Pennsylvania, collected October 17, 1910; 

 C. M. Cat. No. 61.4742. 



Fig. 3. Anodonta grandis footiana (Lea). The form of the beach-pools, from Lake 

 Erie, beach-pools of Presque Isle, Erie, Erie Co., Pennsylvania, collected June 2, 1908; 

 C. M. Cat. No. 61.3651. 



Fig. 4. Anodonta grandis footiana (Lea). Female of the form found in Presque 

 Isle Bay, from Lake Erie, Presque Isle Bay (flats near west end), Erie, Erie Co., Penn- 

 sylvania, collected July 8, 1910; C. M. Cat. No. 61.4733. 



Fig. 5. Anodonta cataracta Say. Creek-form, about half-grown, from Wliite 

 Clay Creek, Avondale, Chester Co., Pennsylvania, collected April 26, 1909; C. M. 

 Cat. No. 61.4167. 



