THE SKIN AND SKELETON. 



143 



BONES OF THE MAMMALIAN SKULL* 



BRAIN-CASE. 



SUPRAOCCIPITAL. 



FRONTAL. PARIETAL. 

 HRYMAL. SQUAMOSAL. 

 NOSE. ORBITOSPHENOID. EYE. ALISPHENOID. PERI- EAR. OTIC. EXOCCIPITAL. 



MALAR. TYMPANIC. 

 PRESPHENOID. BASISPHENOID. BASIOCCIPITAL. 



VOMER. 



PREMAXILLA. MAXILLA. PALATINE. PTERYGOID. 

 LOWER JAW, OR MANDIBLE. 



HYOID ARCH. 



THE SKULL OF THE DOG. 



Fig. 108.— Under surface. Fig. 109.— Upper surface. Fig. 110.— Longitudinal ver- 

 tical section; one-half natural size: SO, supraoccipital ; ExO, exoccipital ; BO, 

 basioccipital ; IP, interparietal ; Pa, parietal ; Fr, frontal ; Sq, squamosal ; Ma, 

 malar; L, lachrymal ; Mx, maxilla ; PMx, premaxilla ; Na, nasal ; MT, maxillo- 

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

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

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

 pterygoid; Per, periotic ; Ty, 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 ; sf, 

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

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

 men lacerum medium; gf, glenoid fossa; gp, postglenoid process; pgf, post- 

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

 fip, foramen lacerum posterius ; cf, condylar forameu ; pp, paroccipital process; 

 oc, occipital condyle ; fm, foramen magnum ; a, angular process ; s, symphysis 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 ; sh, eh, ch, bh, th, hyoidean ap- 

 paratus, or os linguce, supporting the tongue. In the skulls of old animals, 

 there are three ridges: occipital, behind; sagittal, median, on the upper surface; 

 and superorbital, 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 -facial 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. 



