THE SKIN AND SKELETON. I43 



BONES OF THE MAMMALIAN SKULL * 



BRAIN-CASE. 



VOMER. HYOID ARCH. 



PREMAXILLA. MAXILLA. PALATINE. PTERYGOID. 

 LOWER JAW, OR MANDIBLE. 



THE SKULL OF THE DOG. 



Fig. 108.— Under Burface. Fig. lf)9.— Upper surface. Fig. UO.—Longitudinal ver- 

 tical section; one-half natural size: -SO, supraoccipital ; JSajO, exoccipilal ; BO, 

 basioccipital ; /P, interparietal; Pa, parietal; jFV, frontal ; Sg, squamosal ; Ma, 

 malar; Z^, lachrymal ; Jfa;, maxilla ; PJIfa;, premaxilla ; ^n, nasal ; JfT, maxillo- 

 turbinal : ET, ethmoturbinal ; ME, ossitied portion of the mesethmoid ; CE, cri- 

 briform, or sjeve-like, plate of the ethmoturbinal ; VO, vomer ; PS, presphenoid ; 

 OS, orbitospheuoid ; AS, alispheuoid ; BS, basisphenoid ; PI, palatine; Pt, 

 pterygoid; Per, periotic ; 2'y, tympanic bulla; an, anterior narial aperture; ap, 

 or apf, anterior palatine foramen ; ppf, posterior palatine foramen ; io, infra- 

 orbital foramen ; pof, postorbital process of frontal bone ; op, optic foramen ; s/, 

 sphenoidal fissure ; fr, foramen rotundum, and anterior opening of alisphenoid 

 canal ; as, posterior opening of alisphenoid canal ; fo, foramen ovale ; Jim, fora- 

 men lacernm medinm ; gf, glenoid fossa ; gp, postglenoid process ; pgf, post- 

 glenoid foramen ; earn, external auditory meatus; sm, stylomastoid foramen; 

 fip^ foramen lacernm posterins ; cf, condylar foramen ; pp, paroccipital process ; 

 oc, occipital condyle ; fm, foramen magnum ; a, angular process ; s, sym^^hysis of 

 the mandible where it unites with the left ramus ; id. Inferior dental canal ; cd, 

 condyle ; cp, coronoid process ; the * indicates the part of the cranium to which 

 the condyle is articulated when the mandible is in place; the upper border in 

 which the teeth are implanted is called alveolar ; sit, eh, ch, bk, th, hyoidean ap- 

 paratus, or 08 lingucB, supporting the tongue. In the skulls of old animals, 

 there are three ridges: occipital, behind; sagfi(faZ, median, on the upper surface; 

 and auperorbital, across the frontal, in the region of the eyebrows. The last is 

 highly developed in the Gorilla and other Apes. 



* In this diagram, modified from Huxley's, the italicized bones are single ; the 

 rest are double. Those in the line of the Ethmoid form the Cranio -/adal Axis: 

 these, with the other sphenoids and occipitals, are developed in cartilage; the rest 

 are membrane bones. In the Human skull, the four occipitals coalesce Into one. 



