INTRODUCTION. 



men), and of the body of the sphenoid bone ; which latter, together with 

 the ethmoid, intervenes between the skull and the nasal cavities, and 

 enters into the division and arrangements of these cavities.* 



The face is situated anteriorly to the vault of the skull, and, in Man, 

 below its frontal portion. It consists, in the human subject, of fourteen 

 bones, viz., two nasal, two lachrymal, two superior maxillary, two malar, 

 two palate, two turbinated bones, one vomer, one inferior maxillary. In 

 the lower Mammalia, however, two additional bones may be reckoned, 

 viz., the intermaxillary, in which are implanted the incisor teeth : these 

 bones, indeed, exist separately in the human subject at an early stage, but 

 soon become united indissolubly with the superior maxillary, to which, 



in other Mammalia, they 

 remain affixed only by 

 a suture. The annexed 

 illustration (fig. 16) will 

 convey a clear idea of the 

 respective situation and 

 connexion of the bones 

 of the skull and face. It 

 represents a section of the 

 human skull, with the ex- 

 ception of the lower jaw. 

 Though the contour of 

 the face varies throughout 

 the different groups of the 

 Mammalia, and though 

 its relative situation and 

 magnitude, with regard 

 to the cranium, are perpetually altered, still it is made up of the same 

 aggregate of parts as in Man, however they may be modified in detail : 

 they bear, also, the same general relationship among each other, and 

 form the same hollows, or chambers, for the same organs of sense. The 

 orbits of the eye, for example, in the human skull, are bounded within, 



* In the lower Mammalia, the number of the distinct bones entering into the formation of the skull, 

 varies, because certain of the bones which, in Man, become consolidated into single pieces, often, in the 

 former, remain subdivided into their pristine elements through life : such is the case with the temporal 

 and occipital bones. Hence Meckel observes, that " the number of bones which, in the adult and 

 normal state, compose the skull of mammals, cannot be fixed by a general rule, because it is subject 

 to variation ; yet, it may be said never to exceed twenty-eight, of which eleven are proper to the 

 cranium, seventeen to the face." In the Rodentia, for example, the squamous portion of the tem- 

 poral bone remains distinct from the petrous ; and the tympanic bulla is often separate also. The 

 occipital bone usually consists of a basilar, or occipital portion, and an upper, or squamous portion, 

 which is sometimes unconsolidated ; while, anterior to this, in many Rodentia, and other animals, 

 an interparietal bone, of variable size and figure, intervenes between the posterior angles of the 

 two parietals. The sphenoid bone is also divided into two portions, an anterior and posterior : the 

 posterior is formed of the body of the sphenoid and the alse majores ; the anterior portion gives off 

 the alae minores. 



Fig. 16. Section of the Human Skull a, frontal bone ; 6, parietal bone ; 

 c, c. occipital bone ; d, temporal bone ; e, e, sphenoid bone ; f, f, ethmoid 

 bone ; </, nasal bone ; h, turbinate bone ; t, ', i, superior maxillary bone ; k, 

 palate bone ; I, vomer; m, frontal sinus. 



