The Shell-Collector’'s Handbook. 53 
narrow ; hinge line nearly straight ; anterior teeth arched, 
crenated, very much compressed; hinder teeth of left 
valve small or evanescent; ligament longer than in 
U. tumidus. Length of shell 2-3 inches. 
7, Up lf 
1 Oe I) 
HH /h Wy 
“| IH} Wy / 
0 PREAH RL es f yy: 
i il| |) WT 
| | | 
| } bil | | 
i [ } 
BA 
SS AVA jy 
S Z yyy, 
E BB Yih) 
Fig. 1.— Unio Pictorwm. 
Habitat.—Ponds, lakes, and slow-running streams. 
v. radiata (Mogq.): Shell yellowish, with green rays. 
