THE SPECIAL SENSES 229 
In mammals taste organs are situated on certain parts of 
the tongue, and have the form of rather large, low, broad 
papille, each bearing many small taste-buds (Fig. 142). 
In fishes similar papille and buds have been found in vari- 
ous places on the sur- 
face of the body, from 
which it is believed that 
the sense of taste in 
fishes is not limited to 
the mouth. In insects 
the taste-papille and 
taste - pits are grouped 
in certain places on the Fra. 142.—Vertical section of large papilla on 
mouth parts, being es- a of a calf; ¢.0,, taste-buds, — After 
pecially abundant on 
the tips of small, segmented, feeler-like processes called 
palpi, which project from the under lip and from the so- 
called maxille. 
121. The sense of smell—Smelling and tasting are closely 
allied, the one testing substances dissolved, the other test- 
ing substances vaporized. The organs of the sense of 
smell are, like those of taste, simple nerve-endings in papil- 
le or pits. The substance to be smelled must, however, 
be in a very finely divided form; it must come to the or- 
gans of smell as a gas or vapor, and not, as to the organs of 
taste, in liquid condition. The organs of smell are situated 
usually on the head, but as the sense of smell is used not 
alone for the testing of food, but for many other purposes, 
the organs of smell are not, like those of taste, situated 
principally in or near the mouth. Smell is a special sense 
of much wider range of use than taste. By smell animals 
can discover food, avoid enemies, and find their mates. 
They can test the air they breathe as well as the food they 
eat. .In the matter of the testing of food the senses of 
both taste and smell are constantly used, and are indeed 
intimately associated. 
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