PELECYPODA—PRIONODESMACEA. 



4*3 



Fig. 534. Ortonella hainesi. (Ohio Geol., VII. After Ulrich. ) 



132. V. terminalis Ulrich. (Fig. 535, £"-*.) 



Ordovicic. 



Beaks terminal. Anterior muscle scars almost hidden. 

 Upper Stones River of Wisconsin, Minnesota. 



Fig. 535. a—c y Vanuxemia dixonensis ; d-f, V. umbonata, right and cardinal views ; 

 g-i, V. terminalis, internal molds, left, right and anterior views • j\ V. rotundata ; k, 

 V. hayniana, right internal mold. (Minn. Surv.) 



