HAMMER-HEADED SHARK. 63 



The head of this Shark,— representations of the upper 

 and under surface of which, on a small scale, are given 

 below, — measured from one eye to the other, is very 

 large and wide; the eyes are furnished with eye-lids, 

 which arise from the internal part of the orbits, the irides 

 are golden yellow, the pupils black; the nostrils are 

 elongated, and open immediately underneath the depression, 

 or notch, in the anterior margin of the laterally expanded 

 portions of the head ; the mouth semicircular, and furnished 

 with three, four, or five rows of teeth, depending upon the 

 age of the specimen ; these teeth are large, sharp, somewhat 

 triangular and curved, with smooth cutting edges when the 

 Shark is young, but serrated afterwards ; the teeth in the 

 upper jaw having their points directed towards the angle of 

 the mouth ; those of the lower jaw have the same direction, 

 but they are narrower. 



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The body is elongated, covered with a skin slightly gra- 

 nulated ; the colour greyish brown above, nearly white be- 

 neath : branchial openings five, all before the base of the 



