FISHERY BULLETIN: VOL 77. NO 1 



main superior hypural and the two inferior 

 hypurals are ossifying in specimens 6.9 mm NL 

 and larger, the single epural by 7.0 mm SL, and 



FlOURE 11, — Development of the caudal fin and supporting 

 bones in Pleuronichlhys verticalis. A, 5,3 mm NL; B. 6,9 mm 

 NL; C. 8.3 mm SL. Ossified ural bones are shown in black; 

 ossified elements of first preural vertebra are stippled, Ural 

 bones include four hypurals, one epural. and the ural centrum 



the small upper superior hypural by 7. .3 mm SL. 

 Sixteen of the 19 caudal rays are supported by the 

 four hypural bones, one by the epural and one each 

 by the neural and haemal spines of the ultimate 

 vertebra. 



The vertebral column begins to ossify at about 

 the same time rays begin forming in the caudal fin 

 (Table 11 ). A 5.6-mm NL specimen which has 2 + 2 

 caudal rays has the first seven haemal processes of 



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