AiriiD^;. 
369 
Fig. 38. 
Amia calva ; head and opercular apparatus (after Shufeldt). 
a, supramaxillary; Ang., augular; D., dentary; Eth., ethmoid; Fr., frontal; 
I.Op., interoperculum; pi., membranous tract between frontals and 
nasals ; k., supplementary dermal bones; La., anterior suborbital (lachry¬ 
mal) ; M.Pt,, metapterygoid ; Mx., maxilla; Fa., nasal; Op., operculum ; 
P.or., posterior suborbital; Pa., parietal; Pmx., premaxilla; Pr.Op., pre¬ 
operculum ; Pst.T., post-temporal; Psto T., supraclaxicle (“ posterotem¬ 
poral ”); Ptf., postfrontal; Qn., quadrate; S.Ang., surangular (coronoid) ; 
S.Op>., suboperculum; S.tp., supratemporal; Sb.o., suborbital; Sg., squa¬ 
mosal ; Sym., symplectic ; 2 -, ossification of Meckel’s cartilage. 
Fig. 39. 
Amia calva ; left pterygo-palatine arcade, etc. (after Shufeldt). 
Brs.R., branchiostegal rays; C.ky., 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; ro., articular facette for operculum ; Sym., symplectic. 
PAET in. 9 B 
