26  Fretp Musrum or Naturat History — Zodtoey, Vor. XI. 
The Sense of Smell — The sense of smell is present in all mammals, with 
the possible exception of the Toothed Whales. Branches of the 
olfactory nerves are present in the upper portion of the nasal pass; 
age, which come in contact with any odorous particles contained 
in the air and which enter the nose. In many species this sense 
is developed to a most extraordinary degree, warning them of 
the approach of other animals at a surprisingly long distance. 
Trappers have learned by experience that, if a trap is touched 
with the bare hand, many species will not approach it for at 
least 24 hours. 
The Sense of Hearing — The organ of hearing is present in all mammals, 
but, as would be expected, is developed in some much more highly 
than in others. It is divisible into three parts: 1, external ear or 
pinna and the auditory canal or meatus; 2, the middle ear or tym- 
panum; 3, the internal ear or labyrinth. The pinna is present in 
most mammals and is generally movably articulated to the skull, 
and by muscular attachment enables the animal to turn it in the 
proper direction to aid in collecting and directing the vibration of 
sound into the meatus. While these ear muscles are present in the 
ear of Man, from long disuse they are no longer functional except 
in rare cases. The middle ear, drum of the ear, or tympanum, as it 
is variously called, which forms the outer wall of the cavity, is 
traversed by a chain of three or four movable small bones, three of 
which are always present and are known, respectively, as malleus, 
incus, and stapes. These bones are variable in size and character 
in different mammals, especially in aquatic species. The malleus 
in mammalian anatomy represents the quadrate bone of the lower 
orders, which there connects the lower jaw with the skull. The 
internal ear, or labyrinth as it is called, consists of three semi-circular 
canals, a vestibule and a cochlea. Here again is found, with the 
exception of the Monotremes, a distinct mammalian character in 
the spiral convolutions of the cochlea. By the vibrations of the 
tympanic mem brane (produced by sound waves) and the small 
bones, the vibrations of sound are transmitted from the exterior to 
the fluid filling the internal ear and are appreciated by the end 
filaments of the auditory nerve, thus enabling the animal to hear. 
The Sense of Taste — The sense of taste concerns us little here and 
will be dismissed with the brief statement that it is chiefly located 
in the papillae on the dorsal surface of the tongue, although 
similar papille are present in other parts of the mouth, such as 
the soft palate, epiglottis, etc. These papillae are each furnished 
with a branch of the glossopharyngeal nerve. 
