434 MITCHILL ON THE FISHES OF NEW-YORK. 



Eyes on the side of the head, and wide apart. Their colour leaden, 

 with silvery in concentric circles. Iris oblong and vertical, like cats, and 

 other land animals of prey. The eyes seem more moveable in their 

 sockets than is usual with fish. 



Mouth wide and voracious. Teeth small, triangular, and without 

 jagged edges. Arranged in rows, one in the upper, and two in the lower 

 jaw. Tongue white and broad. That, and the palate, beset with a de- 

 licate roughness, meeting the finger when it is drawn over their surfaces 

 from the throat toward the lips. 



A row of excretory ducts runs along the upper lip, from one corner 

 of the mouth to the other. Two other rows begin at the angle of the 

 jaw, and run forward toward the nasal orifices, until they disappear and 

 are lost amidst a great number of similar orifices, which distinguish the 

 under side of the snout. These openings are blackish, and make a plain 

 contrast with the whiteness of the skin. The sides and upper part of 

 the snout are perforated with a plenty of similar holes. From them may 

 be squeezed a mucilaginous fluid ; evincing their function of supplying 

 the skin with its slimy covering. 



When this shark is in the water, his back and sides appear greenish. 

 But soon after his exposure to air, and immediately after his death, the 

 hue becomes a pale ash, leaden, or dove, with but trifling variegations. 

 The parts about the mouth, neck, and belly, are of a clear white. The 

 upper side of the pectoral fins, resembles the colour of the back ; the 

 lower partakes of the complexion of the belly. 



The skin is free from scales, spines, and prickles ; when stroked from 

 head to tail it is remarkably smooth ; when felt in the opposite direction 

 there is a resistance so trifling, that it does not amount to a proper rough- 

 ness. 



Pectoral fins large, lunated, and strong. First dorsal stout and some- 

 what triangular, with a capacity, by means of a process behind, to be 



