THE SKIN AND SKELETON. 143 



BONES OF THE MAMMALIAN SKULL* 



BRAIN-CASE. 



NASAL. 



LAC HRYMAL. SQUAMOSAL. 



NOSE. 



STHMOID. 



8UPRAOCCIPITAL. 



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



MALAR. TYMPANIC. 



PRESPHENOID. BA8I8PHENOID. BASIOCCIP1TAL. 



VOMER. HYOID ARCH. 



PREMAJULLA. MAXILLA. PALATINE. PTERYGOID. 

 LOWER JAW, OR MANDIBLE, 



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 ; A'a, nasal ; NT, maxillo- 

 turbimxl: ET, ethinoturbinal ; ME, ossined portion of the mesethmoid; CE, cri- 

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

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

 pterygoid ; Per, periotic ; Ty, tympanic bulla ; an, anterior narial aperture ; ap, 

 r aP^ anterior palatine foramen ; JPPJJ. posterior palatine foramen ; jo^infra- 

 orbital foramen ; pof, postorbital process of frontal bone ; (Coptic foramen ; /, 

 sphenoidal fissure \+^ foramen rotundum, and anterior opening of aliephenoid 

 canal; as, posterior opening of alispbenoid canal 5/0^ foramen ovale ; 



men lacernm medium ; of, gleuoid fossa ; gp, postglenoid process ; pgf, post- 

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

 JQ foramen lacernm posterius ;j^coudylar foramen; pp, paroccipital process; 

 oc, occipital condyle _f n > 9 foramen magnum ; a, angular process ; s, symphysis of 

 the mandible where it unites with the left ramns ; 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 limjiux, supporting the tongue. In the skulls of old animals, 

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

 and super orbital, 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. 



