644 



MAMMALIA. 



II. The projection of the o calcis. 



XX. The metatarsa! bones uf the four ;M. 



YYYYY.The phaluug-es of the toes, or of the lower hands in 



monkeys and other quadrumauous animals. 

 SB 88. The pelvis. 

 11. The vertebrae of the tail, or caudal vertebrae. This 



organ in man coitbists but of a single bone rising out 



of the lower part of the pelvis, and is termed the os 



coccygw.f. 27. 



Bones of the Head and Neck. 

 a. The os froutis joined to its fellow by the sagittal 



suture, 

 o. The parietal bone. 



c. 'I he temporal process of the sphenoid bone. 



d. The lower jaw. 



The malar, or cheek bone. 



/. The superior maxillary bone; g. Inferior do. 

 A. The nasal bone, 



SKELETON OF A HORSE, pi. 52. f. 38. 

 . The posterior maxillary, or jawbone. 



b. The superior maxillary, or upper jaw. 



c. The orbit or cavity in which the rye is contained. 



d. The nasal bones, or bones of the no.-e. 



0. The suture, dividing the parietal bones below, from 



the occipital bones above. 



f. The inferior maxillary bone, containing the upper in- 



cisors or cutting teeth. 



B. The seven cervical vertebras, or bones of the neck. 



C. The eighteen dorsal vertebrae, or bones of the hack. 

 The six lumbar vertebrae, or bones of the loins. 



E. The five sacral vertebrae, or bones of the paunch. 



F. The caudal vertebrae, or bones of the tail. 

 ('. The scapula, or shoulder blade. 



H. The sternum, fore-part of the cheat or breast bone. 



1. The costae, or ribs, seven or eight of which, articu- 



lating with the sternum, are called the true nbs, 

 and the remaining ten or eleven, which are united 

 by a cartilage, are called thejalse ribs. 

 The radius, or bone of the fore-arm. 

 ! The ulna, or elbow, with its process, the olecranon. 



I.. The carpus, or knee, consisting of seven bones. 



NN. 1'he metacarpal, or shank bones; the large metacar- 

 pal, or cannon, or shank in front, and the smaller 

 metacarpal, or splent bone behind, g. The fore- 

 pasteru and foot, consisting of the os suffrag-inis, 

 or upper and lunger pastern bone, with the sesumoid 

 bones behind, articulating with the common and 

 greater pastern ; the os coronse, or lesser pastern, 

 the os pedis, or coffin bone, and the os navicular, 

 or shuttle bone, not seen, and articulating- with 

 the smaller pastern and coffin bones ; h. the cor- 

 responding- bones of the hind feet. 



OO The small metacarpal, or splent bones. 



P. The pelvis, or haunch, consisting of three portions ; 



the ilium, the ischium, and the pubis. 



QQ. The femur, or thigh bones. 



Kit. The patellH, placed on the stifle joint. 



SS. The tibia, and fibula (the latter is a small bone behind) 

 are also called the ham bones. 



TT. The bones of the tarsus, or hock, six in number. 



UU. The metatarsals of the hind leg, called shank or com- 

 mon bones. 



WW The os calcis, or point of the hock. 



XX. Tne sesamoid, or fetlock bones. 



The upper jaw of the whole mammalia is fixed 

 immovably to the cranium ; the lower jaw consists 

 of two pieces, uniting in the centre of the chin, and 

 articulated by a projecting condyle to a fixed tem- 

 poral bone. The neck is composed of seven verte- 

 brae, and in one species it consists of nine. The 

 anterior ribs are attached to a sternum, formed of 

 several vertical pieces. The anterior extremities or 

 arms commence at the scapula, or shoulder-blade. 

 This bone is not articulated to any other, but simply 

 suspended in the muscles, by thin attachments, and 

 frequently resting on the sternum by the clavicle or 

 collar bone, which holds an intermediate situation ; 

 this is prolonged into an arm, fore-arm, and termi- 

 nated by a hand, consisting of two rows of small 

 bones, denominated the carpus, another row called 

 the metacarpus* and finally the fingers, each com- 

 posed of two or three bones, called phalanges. 



The whole class, with the exception of the 

 Cetacea, have the posterior extremity fixed to the 

 spine, where it spreads out into a pelvis. In young 

 animals, this part is divided into three pairs of 

 bones ; the ilium, or that part attached to the 

 spine ; the pubis, which forms the anterior portion of 

 the pelvis, and the. ischium, which forms the posterior 

 part. At the place where these bones unite, there 

 is a cavity into which the thigh bone is articulated, 



to which is attached the leg, composed of two bones, 

 the tibia and fibula. The leg is terminated by a 

 toot, composed of parts analogous to those of the 

 hand, and are termed the tarsus, metatarsus, and 

 toes. The termination of the lower extremities of 

 the animals, comprising the order quadrumana, can- 

 not be termed a foot, as it is in every respect analo- 

 gous to the hands of the upper extremities, and hence 

 the name of the order, four-handed. It will be 

 readily seen, by comparing the hands of the upper 

 and lower extremities of the Orang-Outang, (Pithaus 

 satyrus) plate LIL, figures 23 and 24, that they 

 are both formed for grasping. Fig. 23 is the hand 

 of the upper extremity or arm, and tig. 24 the hand 

 of the lower extremity or leg; a hind hand of the 

 Aye-aye, (Cheiromys Madagascarcnsis) is also re- 

 presented at fig. 45. 



The CRANIUM in the mammalia is always articu- 

 lated by two condyles upon the atlas bone, or first 

 vertebra of the neck. 1'he cranium is divided into 

 three compartments ; the fore part is formed of the 

 two frontal bones and the ethmoid ; the interme- 

 diate, by the parietal bones and the sphenoid ; and 

 the posterior by the occipital. Between the occipital 

 bones and the sphenoid, are inserted the temporal 

 bones, a part of which properly belong to the face. 



In the foetus the occipital bone is divided into four 

 parts ; the body of the sphenoid into two, and three of 

 its pairs of alae are separate. The temporal bone con- 

 sists of three divisions, one of which serves to com- 

 plete the cranium, another to close the labyrinth of 

 the ear, and the third to form the sides of its cavity. 

 These parts of the bones of the cranium unite more 

 or less quickly, and are perfectly united in the adult. 



The face is formed by two maxillary bones, 

 between which the nasal canal passes ; they have 

 the two intermaxillary bones in front, and the pala- 

 tine behind ; between these descends the single 

 lamina of the ethmoid bone, called the Vomer. At 

 the entrance of the nasal canal, are the bones proper 

 to the nose. The jugal, or cheek bone of each side, 

 unites the maxillary bone to the temporal, and often 

 to the frontal bones; and finally, the lachrymal 

 occupies the internal angle of the orbit, and some- 

 times a part of the cheek. 



The BRAIN is composed of two hemispheres, 

 united by a medullary lamina, called the corpus cal- 

 losum, and contains two ventricles, enclosing four 

 pairs of tubercles, which are termed corpora striata, 

 the thalami optici, nates and testes. Between the 

 thalami optici is a third ventricle, which communi- 

 cates with a fourth, situated under the cerebellum. 

 The crura of the cerebellum form always under the 

 medulla oblongata a transverse prominence called 

 pans Varioli. 



The EYE is always situated in the orbit ; it is 

 protected by two eyelids, and the rudiments of a third. 

 The crystalline lens is fixed by the ciliary process 

 and its cellular sclerotic coat. 



The EAR has universally a cavity called the tym- 

 panum or drum, which is closed from without by the 

 membrana tympani; it has also four bones called the 

 incus, malleus, stapes, and os orbiculare at the 

 entrance of which is placed the stapes, which com- 

 municates with these circular canals; finally, a spiral 

 canal called the cochlea, which terminates by one of 

 its canals in the tympanal cavity, and by the other in 

 the vestibule. 



The TONGUE is always fleshy, and attached to the 

 hyoid bone, suspended by ligaments in the cranium. 



The organ of VOICE is always placed at the superior 

 extremity of the trachea; and a fleshy continuation, 

 denominated the Velum palati, or soft palate, estab- 

 lishes a distinct communication between the larynx 

 and back part of the nostrils. 



