Note d — BOOK IV.

Moles have no protuberant Ear, but only a round Hole between the Neck and Shoulder; which Situation of it, together with the thick, short Fur that covers it, is a sufficient Defensative against external Annoyances. The Meatus Auditorius is long, round and cartilaginous, reaching to the under part of the Skull. Round the inside runs a little Ridge, resembling two Threads of a Skrew; at the Bottom whereof is a pretty Inlet, leading to the Drum, made, on one side with the aforesaid cochleous Ridge, and on the other, with a small Cartilage. I observed there was Cerumen in the Meatus.

As to the inner Ear, it is somewhat singular, and different from that of the other Quadrupeds, and much more from Birds, although I have met with some Authors that make it agreeing with that of Birds. There are three small Bones only (all hollow) by which the Drum (to use the old Appellation) or the Membrana Tympani (as others call it) acteth upon the Auditory Nerve. The first is the Malleus, which hath two Processes nearly of equal Length; the longer of which is braced to the Membrana Tympani, the shorter to the side of the Drum or Os Petrosum; the back part of it resembles the Head and Stalk of a small Mushroom, such as are pickled. On the back of the Malleus lies the next small Bone, which may be called the Incus, long, and without any Process, having somewhat the Form of the short Scoop wherewith Water-men throw the Water out of their Wherries. To the end of this the third and last small Bone is tacked by a very tender Brace. This little Bone bears the Office of the Stapes, but is only forked without any Base. One of these Forks is at one Fenestra, or Foramen, the other at another; in which Fenestra I apprehend the Forks are tacked to the Auditory Nerve. These Fenestra (equivalent to the Fenestra Ovalis, and Rotunda in others) are the Inlets into the Cochlea and Canales Semicirculares, in which the Auditory Nerve lieth. The Semicircular Canales lie at a distance from the Drum, and are not lodged (as in other Animals) in a strong, thick Body of Bone, but are thrust out, within the Skull, making an Antrum, with an handsome Arch leading into it, into which a part of the Brain enters.

One Leg of the Malleus being fastned to the Membrana Tympani, and the Incus to the back of the Malleus, and the top of that to the top of the Stapes, and the Forks or Branches of the Stapes to the Auditory Nerve, I observed that whenever I moved the Membrane, all the little Bones were at the same time moved, and consequently the Auditory Nerve thereby affected also.

I hope the Reader will excuse me for being so particular in this Organ only of the Mole, a despised Creature, but as notable an Example of God’s Work, as its Life is different from that of other Quadrupeds; for which Reason it partly is that I have enlarged on this part differing from that of others, and which no Body that I know of, hath taken much notice of, and which is not discoverable without great Patience and Application; and partly because by comparing these Observations with Book VII. Chap. 2. Note (d), we may judge how the Sense of Hearing is performed.