JAWS 



97 



FIG. 50. 



Diagrams of, A and D, an amphistylic skull (Heptanchu*), B and E, an autostylic skull (Rana), 

 and C and F, a hyostylic skull (Scyllium). A, B, and C, left-side views. D, E, and F from 

 behind (the mandibular arch being dotted; and the cranium shaded), c, columella auris ; ch, 

 ceratohyal ; cr, cranium ; e, junction of ethmoid and palatine cartilages ; e.p, ethmoid process ; 

 /i, hyomandibular branch of facial nerve ; h.a, hyoid arch ; hm, hyomandibular ; I, labial ; mfc, 

 Meckel's cartilage ; TOT, nasal capsule ; o.a, junction of otic process of quadrate with the auditory 

 capsule ; o.p, otic process ; pd, palato-basal process ; pi, palatine rejion ; p.n, palatine branch of 

 facial nerve ; po, preorbital process ; po.p, postorbital process ; pt, palato-quadrate cartilage ; q, 

 (piadrate region ; r, rostral process ; sp, spiracle ; t, tympanum. 



