﻿Fig. 
  38. 
  

  

  369 
  

  

  S- 
  C 
  /J 
  -Pa 
  

  

  Amia 
  calva 
  ; 
  head 
  and 
  opercular 
  apparatus 
  (after 
  Shufeldt). 
  

   a, 
  supramaxillary 
  ; 
  Aug., 
  angular 
  ; 
  D., 
  dentary 
  ; 
  Eth., 
  ethmoid 
  ; 
  Ft., 
  frontal 
  ; 
  

   I. 
  Op., 
  interoperculum 
  ; 
  pi., 
  membranous 
  tract 
  between 
  frontals 
  and 
  

   nasals 
  ; 
  Jc., 
  supplementary 
  dermal 
  bones 
  ; 
  La., 
  anterior 
  suborbital 
  (lachry- 
  

   mal) 
  ; 
  M.Pt., 
  metapterygoid 
  ; 
  Mx., 
  maxilla 
  ; 
  Na., 
  nasal 
  ; 
  Op., 
  operculum 
  ; 
  

   P.or., 
  posterior 
  suborbital 
  ; 
  Pa., 
  parietal 
  ; 
  Pmx., 
  premaxilla; 
  Pr.Op., 
  pre- 
  

   operculum 
  ; 
  Pst.T., 
  post-temporal; 
  PstoT., 
  supraclavicle 
  (" 
  posterotem- 
  

   poral 
  ") 
  ; 
  Ptf., 
  postfrontal 
  ; 
  Qu., 
  quadrate 
  ; 
  S.Ang., 
  surangular 
  (coronoid) 
  ; 
  

   S.Op., 
  suboperculum 
  ; 
  S.tp., 
  supratemporal 
  ; 
  Sb.o., 
  suborbital 
  ; 
  Sq., 
  squa- 
  

   mosal 
  ; 
  Sym., 
  symplectic 
  ; 
  z, 
  ossification 
  of 
  Meckel's 
  cartilage. 
  

  

  Fig. 
  39. 
  

  

  5.Jy 
  

  

  Amia 
  calva 
  ; 
  left 
  pterygo-palatine 
  arcade, 
  etc. 
  (after 
  Shufeldt). 
  

  

  Brs.B., 
  branchiostegal 
  rays; 
  C.hy., 
  ceratohyal; 
  E.hy., 
  epihyal 
  ; 
  Ecpt, 
  ecto- 
  

   pterygoid 
  ; 
  Enpt., 
  entopterygoid 
  ; 
  H.hy., 
  hypohyal 
  ; 
  H.M., 
  hyomandibular 
  

   M.Pt., 
  metapterygoid; 
  PL, 
  palatine; 
  Pr.Op., 
  preoperculum 
  ; 
  Qu., 
  quad- 
  

   rate; 
  to., 
  articular 
  facette 
  for 
  operculum 
  ; 
  Sym.., 
  symplectic. 
  

  

  PART 
  III. 
  2 
  B 
  

  

  