Atwood.] 268 [January 20, 



Capt. N". E. Atwoo J presented the following description of 

 a shark, Carcharias tigris Atwood. 



The whole upper portion of the back dark blue ; this color extends 

 eiglit inches down the sides of the body from the anterior portion of 

 the first dorsal; below this there is a band, eight inches broad at this 

 point, of a light leaden color, running the entire length of the body, 

 but becoming narrower as it extends forwards and backwards, in pro- 

 portion as the circumference of the fish diminishes ; the edge of this 

 coloring is very uneven. Gape of the mouth large; both jaws armed 

 with four prominent rows of visible teeth; other rows, lying behind, 

 are flat and covered by the membrane; the largest teeth are near the 

 tip of the lower jaw and me:isure 1^ inches in length, and \ of an 

 inch in breadth, at the base ; they are smooth and curve inwards. 



Lengtli 8 feet 10 inches. Breadth at the origin of the first dorsal 

 22 inches; at the extremities of tlie ventrals 10 inches; distance from 

 the tij) of the pointed snout to the first branchial orifice 2 feet; from 

 the first to the fifth, and last branchial orifice 5 inches; branchial 

 apertures about 9 inches in length, nearly equal; from the tip of the 

 snout to the eye 8 inches; the nearly circular eye 1-^ inches in diame- 

 ter; distance between the eyes 7^ inches; the nostrils are placed 2|- 

 inches in front of the eyes. 



The anterior portion of the first dorsal is placed 3 inches behind 

 the pectorals; it is 13 inches high and 12 inches long at the base, 2|- 

 inches of the posterior extremity remaining unattached. The second 

 dorsal is placed 25 inches behind the posterior edge of the first dorsal; 

 it is 2^ inches high and 4 inches long at the base, 3 inches of its poste- 

 rior extremity remaining free; distance from the jjosterior extremity of 

 this fin to the base of the caudal 7 inches. Pectorals 23 inches high 

 and 1\\ inches long at the base, 4 inches remaining unattached. 

 The anterior portion of the ventrals arises on a line opposite the mid- 

 dle of the space between the two dorsals; they are four inches high 

 and eight inches long at the base, three inches of the posterior ex- 

 tremity remaining free. The anal fin arises one inch behind a jjoint 

 opposite the front of the second dorsal, with which it corresponds in 

 form and size. The upper lobe of the caudal, measuring from the 

 anterior edge of the base is 23 inches in length, the lower lobe 18 

 inches; the tips of its lobes are 31 inches apart; the centre of this fin 

 measures 9 inches in breadth. 



The first specimen of this ver}- rare shark was brought from the 



