Selachians Extraordinary 281 



Guitarfish swim by propelling themselves with their tails. (Their pec- 

 toral fins are merely used as planes to raise, lower, or turn their bodies.) 

 The underside, containing the gills, is flattened like a skate or a ray. This 

 duality persists in its habits— sometimes, like a skate or a ray, it lies 

 half-buried in the sand or mud; other times, it swims, though usually 

 hugging the bottom. 



Except for oystermen who accuse the Guitarfish of devouring oyster 

 and clam beds by burrowing through them at a gluttonous pace, and 

 ichthyologists who are intrigued by the Guitarfish's biological oddity, 

 not many people are interested in the Guitarfish. Game fishermen look 

 upon them with little interest, too, for often a hook and line is not even 

 needed to get them; they lie in shallow water and can be plucked from 

 the sea by the tail. They are scooped up in nets near shore by fishermen 

 in India, where they are called Plowfish because their burrowing along 

 the bottom often leaves furrows on the ocean floor. 



Family Pri^^/W^^— Sawfishes 



The Sawfish is one of the strange forms generated by the mysterious 

 evolutionary forces which have molded so many other curious types 

 of Selachians. Its long, flat snout resembles a saw with wide-spaced 

 teeth. These teeth— 16 to 32 on each side of the "blade," depending on 

 the species— are actually specialized dermal denticles. 



(Unlike the teeth found in the mouths of sharks, the saw teeth on 

 the Sawfish's snout are deeply and firmly embedded in sockets in the 

 hard cartilaginous "saw." This may be an evolutionary development, for 

 the fossil remains of some prehistoric Sawfish do not have sockets for 

 the saw teeth, which were then apparently only attached to the skin.) 

 These saw teeth are sharp, and, according to reliable reports, can be 

 lethal. Sawfish are particularly feared in Panama City Bay, where several 



A Sawfish ( Pristis clavata ) . 



Courtesy, Harvard Museum of Comparative Zoology 



