ORGANS OF SMELL. 31 



close its cavity. Of the three ossicles, that which corresponds to 

 the malleus is nearly triangular, departing very much from its usual 

 form, and being provided with a long pointed process. The stapes 

 has only a very fine opening, or is solid. The external meatus is 

 not formed of bone, and is excessively narrow and tortuous. The 

 external opening of the ear is so small, that it is scarcely visible. 



Organs of Smell. 



All Mammalia, with the exception of the Cetacea, have an eth- 

 moid bone, often of great breadth, the cribriform plate perforated 

 with numerous holes, and the ethmoidal labyrinth well developed. 

 In the Apes the ethmoid is narrower than in Man, the crista galli 

 is wanting (even in the Orang-utang), and it exhibits few openings. 

 It is larger and very much perforated in the Pachydermata, the 

 Ruminantia, and especialiy in the Carnivora. Of the three tur- 

 binated bones, the inferior is in particular frequently developed 

 to a surprising degree, and consists of a pair of much convoluted 

 laminae, as in the Ruminantia, some Rodentia and Pachydermata. 

 Other Rodentia, as the Hare, Beaver, Squirrel, have more the 

 complex structure of the Carnivora, in which the nasal cavity, 

 though spacious in animals generally, is the largest of all, The 

 turbinated bone is here divided into a number of jagged lateral 

 laminae, so that, on a transverse section, it seems like a branching 

 tree. The nasal sinuses are generally present, but exhibit great 

 differences in the separate orders and genera, and are least de- 

 veloped in the Rodentia and Cetacea. The frontal sinuses are 

 sometimes remarkably large, the wide intercommunicating bony 

 cells penetrating even into the temporal and occipital bones, while 

 in many animals, as the Marten, the Badger, the Rhinoceros, they 

 are entirely wanting. In the Ruminantia they enter the frontal 

 prominences upon which the horns are situated. The superior 

 maxillary cavities are small in the Apes, and disappear entirely in 

 the Carnivora, Edentata, and Rodentia ; in the Pachydermata they 

 are of moderate size ; they are very large in the Horse, and in the 

 Ruminantia. The sphenoidal sinus is enormously developed in the 

 Elephant, and extends even into the alary processes of that bone ; 

 yet the frontal sinuses are here wanting. The nose is formed, as 

 in Man, partly of cartilage ; its muscles are often powerfully de- 

 veloped, and there is a special dilator. There is found very gene- 

 rally also, as in Birds, a peculiar nasal gland, which is, however, 



