8o 



COMPARATIVE MORPHOLOGY OF VERTEBRATES 



TABLE OF THE PRINCIPAL CRANIAL BONES 

 Notochord 

 Parachordals 



Cranium 



Chondrocranium 



Trabeculae 

 Ethmoid plate 



Sense cap- 

 sules 



Otic 



Optic 

 Nasal 



Membrane bones 



Roofing bones 



Lateral line 



Visceral 

 skeleton 



Maxillary arch Membrane bones 



Pterygoquadrate 

 cartilage 



Membrane bones 



-,,.,, , J Meckel's cartilage 



Mandibular arch i 



Membrane bones 



Hyoid arch 



Gill arches 



Basi-, ex-, and supra- 



occipitals 

 I Basi- and ali-, pre- and 

 1 orbitospbenoids 



Mes- and ectethmoids 



Pro-, epi-, opisth-, pter- 

 and sphenotics (petro- 

 sal) 



(Sclerotics) 



Lateral ethmoid, tur- 

 binals 



Parietals, frontals, na- 

 sals, pre- and post- 

 frontals, supra- and post- 

 orbitals, supratemporal 

 ' Lacrimals, infraorbitals 



Premaxillary, maxillary, 



zygomatic, quadratojugal, 



squamosal 



Pterygoid (ect-, ent-, epi-, 



mesopterygoids), quadrate 



(incus) 



Palatines, vomers 

 i Articulare, (malleus), men- 

 1 to-Meckelian 



Dentary, splenial, coro- 

 noid, angulare (tym- 

 panic), surangulare, 

 goniale 



Hyomandibulare (stapes), 

 symplectic, interhyal, epi- 

 cerato-, hypo- and basi- 

 hyal (corpus, copula), col- 

 umella (lesser cornua) 

 Pharyngo-, epi-, cerato-, 

 hjrpo-, basi-, hyobran- 

 chial (copula, greater 

 cornua) 



The ear bones or ossicula auditus are best treated together here, 

 although their consideration requires the mention of structures not 

 yet described. The ear bones occur only in the tetrapoda; they pre- 

 sent several modifications not readily homologized with each other, 

 though they all have the same function of conveying sound waves 

 across the tympanum to the inner ear. In all there is an opening, the 



