 Nathaniel Shaler left his humanist studies and joined Agassiz 's lab at Harvard University , having already read Agassiz 's introductory essay on classification . His autobiography details his initial interactions with Agassiz . With regard to his first assignment , Shaler recorded that Agassiz brought him a small fish to study with the stipulation that Shaler not discuss it with anyone or read anything on the topic until Agassiz had given him permission . When Shaler asked Agassiz for more explicit instructions , Agassiz replied that he could not be more explicit than saying " [ f ] ind out what you can without damaging the specimen " . After the first hours , Shaler thought he had " compassed that fish , " but despite Agassiz always being " within call " he was not asked to present his conclusions . During the course of the following week , Shaler recorded the details of " how the scales went in series , their shape , the form and placement of the teeth , etc . " 
