Dąbrowski has an unidentified “Symbols of American Freemasonry”, see below. I don’t know in which degree this image is featured and if there are other systems or degrees with this symbol. Interesting in this regard is this, a suggestion that the ear to to be connected to the Level and thus to the Senior Warden.
In Webb’s Monitor, Morris’s Edition (1872) there is an image with a ear, a mouth and a chest in the section about the second degree.
Perhaps the answer lays in the following quote, still within the Fellowcraft section, but some 60 pages further:
The attentive ear receives the sound from the instructive tongue, and the mysteries of Masonry are safely lodged in the repository of faithful breasts.
Top: Dąbrowski P. 160. Year and designer unknown.
Bottom: Webb’s Monitor, Morris’s Edition (1872)