38 MAMMALIA. 



Cheiroptera. They are very large in the Hamster and other Ro- 

 dentia, where they extend deeply down the neck, and are compres- 

 sed by peculiar tegumentary muscles which arise from the spinous 

 processes of the vertebrae, being detached from the trapezius mus- 

 cle. The cavity of the mouth is usually smooth internally ; some- 

 times, however, as in the Ruminantia, it is beset with hard tubercles, 

 which are very hard and horny on the palate of Echidna. The pal- 

 ate is frequently provided with deep transverse furrows and pro- 

 jecting elevations. Some Rodentia, such as the Beaver and Hare, 

 have a spot upon the inner surface of the cheek beset with hairs. 

 The velum palati is more or less scooped out into a semilunar form ; 

 the uvula is wanting in nearly all animals, even in the Makis ; and 

 in the Apes where it occurs, it is smaller than in Man. In the 

 Elephant the velum palati is very long ; as also in the Cetacea, 

 where it is drawn very far back. The mucous glands are more or 

 less developed ; in the zygomatic groove in the cheek, they not 

 unfrequently form a ragged conglomerate gland (glandula buccalis), 

 with several excretory ducts, which sometimes extends even into the 

 orbit and zygomatic fossa. The tonsils are generally met with ; 

 they are largest in rapacious and carnivorous animals, as in the 

 Bears and Cats ; they are, on the contrary, very small in the 

 Mustelidse ; in the Rodentia they are most feebly developed, and ex- 

 hibit in general great diversities in the several orders. In the Apes 

 even they are different. In the Lion and some other Cats, each ton- 

 sil forms a sac, in which the fluid secreted accumulates. A peculiar 

 formation occurs in the Camel ; there is here found a singular de- 

 velopment of the velum palati, which is called the bursa faucium, 

 as a moveable duplication of the velum containing many glands, 

 which occurs in its full development pnly in the male, and in the 

 rutting season swells out so much as to protrude from between the 

 teeth. 



The Tongue has already been considered as the organ of taste. 

 In some animals, as the Dog and Cat, there is found in its middle 

 line covered by flesh a band-shaped fibre-cartilage, called the worm. 

 The lingual or hyoid bone is generally present, but exhibits very 

 diversified forms. It is in its simplest condition in the scaly animals, 

 as the Manis, where it forms only a slender arch, and exhibits no 

 traces of peculiar cornua. It is of considerable size, and pro- 

 vided with two cornua in the Ornithorynchus and Echidna ; in the 

 latter the posterior cornu consists of three pieces. In the Cetaceaj 

 as the Dolphin, the body of the lingual bone is flat, and there are 



