 The sicklefin lemon shark has a robust , stocky body and a short , broad head . The snout is rounded or almost wedge @-@ shaped , with small nostrils bearing triangular flaps of skin in front . The eyes are small , with no spiracles . Short furrows are present at the corners of the mouth . Thirteen to 16 ( usually 14 ) tooth rows occur on either side of both jaws , not including the tiny teeth at the symphysis ( the jaw midline ) . The upper teeth have a large cusp rising from a broad base , with a notch on each side ; these teeth become increasingly angled towards the corners of the mouth . The lower teeth resemble the upper teeth , but are narrower and more erect . The teeth of sharks over 1 @.@ 4 m ( 4 @.@ 6 ft ) long are finely serrated . 
