l8o BULLETIN OF THE NEW YORK STATE MUSEUM 



Unio complanatus, Sol. 



Fig. 6 



Beaks with four to six sharp undulations, which are 

 rounded anteriorly and angular posteriorly, and which have 

 fine, direct converging lines on both dorsal areas. Lateral 

 portion of each undulation placed nearly parallel to the 

 hinge-line, and not much stronger posteriorly than anteriorly. 

 Undulations without any indication of a sinus, and dorsal 

 areas without radiating lines. 



The beaks and other characters of U. complanahis do not 

 indicate any near relationship with any other species of 

 Unio inhabiting this vicinity. The species is, however, 

 closely related to U. declivis in all characters. Dr. Lea in 

 his Synopsis has these two species separated by several 

 pages. Although both are arranged under the same group, 

 it would be better if they were placed nearer to each other 

 in the group. 



Although U. complanatus is one of the most plentiful 

 species in this neighborhood, it is not easy to secure speci- 

 mens having good beaks. 



Unio ochraceus, Say 



Fig. 7 



Beaks with six or seven undulations which are rounded 

 on the summit and placed nearly parallel to the hinge-line. 

 None of undulations have a distinct sinus, but there is some- 

 times a slight bend toward the beak about the middle of 

 the earlier undulations. Posteriorly, the earlier undulations 

 have very faint converging lines. Anteriorly, there are no 

 converging lines but the undulations are rounded and con- 

 tinue up the anterior area nearly to the hinge-line. The 

 dorsal areas lack radiating lines. In most cases there are 

 two slight, linear depressions of the posterior dorsal area 

 which are continued in the later growth of the shell. 

 Usually the very young shell shows the bright green rays 

 which are generally present in the adult state, and in such 



