LEE BARKER WALTON 21 



While the Department Catalogue is the principal one, 

 the other two are important and represent a comparative- 

 ly small amount of labor, inasmuch as a single card con- 

 tains data for a large number of specimens. Classifica- 

 tion of material into groups (e. g., Protozoa, Porifera, 

 etc., in Zoology) can be indicated by using cards with 

 appropriate tabs in different positions, while geographical 

 distribution can be represented, if desired, by different 

 colored cards. 



