Manicules
Though there is little marginalia within Bryan’s textbook, a crudely drawn manicule appears on page 83. The manicule serves as an early form of highlighting to denote an important piece of textual information. As the textbook was undoubtedly used by students, manicules appear to mark important facts and sentences for later reference.
When examining the marginalia up close, the drawing is clearly a manicule. Although it is neither intricate nor well designed, the clear attempt to draw a hand pointing toward a specific piece of text indicates a manicule.