SKULL 



131 



lateral horns covered with hair : these are usually described as 

 separate ossifications which become united with the frontals ; but 

 it has recently been shown that they originate in connection with 

 the fibrous osteogenetic tissue of the parietal bones. 



Dorsally and laterally to the cartilaginous olfactory capsules 

 investing bones arise, viz., the variously-shaped nasals and the 



FIG. 93. EARLY STAGES IN THE DEVELOPMENT OF ANTLERS (A, B) AND HORNS 



(C, 1), E). (After M. Weber.) 



Cor, derm ; Ep, epiclerm ; #$, horny sheath ; HZ, bony process of the frontal, 

 with the epiphysis-like " os oornu" (00} at its apex : the latter is comparable 

 to the beam of the antler, and the former to the pedicle : in E the two are 

 already fused (HZ +00) ; ^?, zone of resorption, at which point the antler 

 is shed ; SZ, process of the frontal still covered with the integument ; &2 1 , 

 the same after loss of the integument. 



lacrymals, each of the latter perforated by a lacryrnal foramen ; in 

 this region also are the lateral plates of the ethmoid (lamina; 

 papyracece). The scroll-like turbinals which are usually well- 

 developed within the olfactory chambers will be described later. 

 Cartilage persists in the adult only in the nasal septum, in the 

 form of the alinasal and aliscptal cartilages. 1 A septomaxillary 



1 An external nose is peculiar to certain Mammals (e.g. Man). Representa- 

 tives of the cartilages mentioned above are present amongst other Amiiiota and 

 in Reptiles, in which, however, they do not extend anteriorly to the rest of the 



K 2 



