ERRATUM. 



The arrangement sketched on page 26 and followed in the tables was 

 made out before the completion of my studies of the classification of the 

 Pelecypods. These being since completed, two changes would follow 

 in the arrangement. The suborder Solenacea would be transferred to 

 the order Teleodesmacea, following the Tellinacea, and the suborder 

 Solenomyacea would be transferred to the Anomalodesmacea. It is also 

 probable that the Isocardiacea should be raised to subordinal rank. 



W. H. Dall. 



August 19, 1889. 



