Negus worked on these specimens , and adding to them with others supplied by the Zoological Society of London .
Negus carried out meticulous dissections that enabled him to trace the stages of evolution and development of the larynx across a wide variety of animals .
Working on these specimens , and adding to them with others supplied by the Zoological Society of London , Negus carried out meticulous dissections that enabled him to trace the stages of evolution and development of the larynx across a wide variety of animals .