



w 







first pterygiophore possesses two and the last pterygio- 

 phore possesses two or three columnar projections. The 

 presence of more than one such projection may indicate 

 that the first and last pterygiophores are fusion products 

 of two or more originally separate basal pterygial ele- 

 ments. The fin rays are articulated by fibrous tissue to 

 these columnar distal ends of the pterygiophores. Like 

 the dorsal fin pterygiophores, the anal fin pterygio- 

 phores are slightly thicker in the middle regions 

 throughout their lengths than they are anteriorly or pos- 

 teriorly. 



Anatomical diversity and generic relation- 

 ships. — The fossil record of tetraodontids is meager. The 

 only relatively complete specimen of a tetraodontid is 

 Tetraodon pygmaeus Zigno (1887b) from the Eocene of 



