174 



RIVER MUSSELS. 



Lea, a Philadelpliia Quaker, who died near the close 

 of the year 1886, aged ninety-four years. To this 

 venerable man the students who live along the inland 

 waters of our country will ever owe a debt of grati- 

 tude. 



Of our few species, all of which have thin shells 

 and slight hinge- teeth, if any, we will first study 

 A^iodonta Californiensis^ Lea, An-o-don'-ta Cal-i-for- 

 Shell very thin, of bluish pearl 



ni-en -SIS, 



Fig. 147. 



Fig. 147. 



within, and covered with a greenish brown epider- 

 mis; almost transparent at the umbones. The hinge- 

 line is prolonged obliquely upward, forming a nearly 

 right triangle above the oval part of the shell. Its 

 length is three inches. The specimen for the 

 engraving was taken from the San Joaquin river. 



