PRIMITIVE PORES OF POLYODON SPATHULA 
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Fig, 5. Photograph of a Polyodon spathula on which the lateral line and its 
branches and the hyomandibular branch and its branchlets had been painted 
white. Many of the groups of primitive pores on the side of the head were inked 
to make them stand out more clearly. The slight humping at the dorsal fin is due 
to the way the fish was suspended. The fish measured about one meter from the 
tip of the bill to the tip of the dorsal lobe of the tail. 
