ASN Nat 
PASAY 
WSO 
» 
Figs. . — Evolution of paired fins. 49-50. Pectoral and ventral fins of Cladose- 
lache. X }. 51. Pectoral fin of Acanthodian, Parexus, (After SMITH WOODWARD.) 52. 
Pectoral fin of Heptanchus. (After GEGENBAUR.) 53. Pectoral fin of Xenacanthus 
(Pleuracanthus.) (After A. FRITSCH.) 54. “Archipterygial” pectoral fin of Ceratodus, 
(After HOWEs. 
B. Basal. D. Dermal. 2. Radial. 
42 
