

Fig. 92. Hj^pothetical Stages in the Development of Fins. The shortening 

 of the single dorsal and paired lateral fins to form the discontinuous dorsal 

 and lateral (pectoral and pelvic) fins according to the fin-fold theory. 



(After Dean). 



B. Ventral View 



Fig. 93. Cladoselache, Side and Ventral Views. A primitive, extinct 

 Elasmobranch with fins having wide bases and numerous radial cartilages. 



(After Dean). 



