PLATE 6 
EXPLANATION OF FIGURES 
All figures of Heterodontus francisei (X 2). 
18 End view of fifth vertebra. 
19-20 Cross-section of fifth vertebra. 
21 End view of fifty-third vertebra. 
22-23 Cross-sections of fifty-third vertebra. 
b.d., basidorsal plate h.a., haemal arch 
b.v., basiventral plate i.d., interdorsal plate 
c., centrum i.v., interventral plate 
ch., notochord n.a., neural arch 
cl.p., calcified plate n, rib 
cl.r., calcified ring s.b.d., suprabasidorsal plate 
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