426 DESCRIPTION OF THE MUSEUM. 



species which is most celebrated for its vora- 

 city is the white shark (squalus carcarias) ; its 

 mouth is armed with a great number of teeth 

 placed in five or six rows ; these teeth, which 

 are extremely hard and white, are in a trian- 

 gular form terminating in a sharp point, having 

 the sides cut like a saw. After these follows the 

 sub-genus of the hammer headed sharks (s. zy- 

 gaena, Guv.), very remarkable for the form of 

 their head, of which there is not another example 

 in the animal kingdom ; it is flattened, and as it 

 were truncated, with the, two sides extended 

 like the head of a hammer, and the eyes at the 

 extremities. We have five species of the zy- 

 gaena ; that which is most common in our seas 

 is sometimes 12 feet long. 



The genus most allied to the sharks is that of 

 the saw-fish, whose distinguishing character con- 

 sists in a very long depressed snout in the form 

 of a beak, furnished at each side with strong 

 prickles fixed in the manner of teeth. This beak 

 is a powerful weapon, with which the saw- 

 fish attacks the largest fish without fear. We 

 have five species of them ; on the ceiling is a 

 large specimen of the most common species 

 (pristis antiquorum, Lath.). The sa w-fish con- 

 nects the sharks and the rays, which M. Cuvicr 

 has divided into seven sub-genera, and of which 



