194 



W. HAROLD LEIGH-SHARPE 



"Arising iinmediately within the point of union of the pubic 

 and ihac regions is the basal cartilage which .... is 

 prolonged backwards into a powerful clasper .... the 

 cartilage becomes more calcified and .... broader. The 



Fig. 2 Pleuracanthus parallelus (after Fritsch.') B., basipterygium ; D.D., 

 dermal denticles; cl,, claspers. A., restoration of Xenacanthus decheni.^ 



inner edge is straight, but the outer edge exhibits a gentle sigmoid 

 curve which results in the widening of the rounded terminal 

 extremity; and at the end of each clasper (especially the left) 



1 Fritsch, Ant., Fauna der Gaskohle und der Kalksteine der Permformation 

 Bohmens— Prag. Bd. 3, Heft I, Taf. 93. 



2 0p. cit., p. 31. 



