42 



FISHERY BULLETIN OF THE FISH AND WILDLIFE SERVICE 



Figure 14. — Above: Dusky shark (Carcharhinus obscurus), female about 39 inches long, Woods Hole. A, third upper 

 tooth; B, fourth lower tooth; C, ninth upper tooth; D, tenth lower tooth; about 2.4 times natural size. Below: 

 Brown shark (Carcharhinus milberti), female, about 4 feet 10 inches long, from Woods Hole. A, ninth upper tooth; 

 B, eighth lower tooth; C, third lower tooth; about 1.4 times natural size. From Bigelow and Schroeder. Drawings 

 by E. N. Fischer. 



(p. 43), with more deeply concave rear margin, 

 its point of origin about over the inner corner of 

 the pectoral (over the armpit of the pectoral in 

 the brown shark); its apex is narrowly rounded. 

 The free rear corner of the second dorsal fin is less 

 than twice as long as the vertical height of the 

 fin. The anal fin is a little longer, along the base, 

 than the second dorsal and stands about under the 

 latter. The caudal fin occupies between one* 

 quarter and one-third of the total length of the 

 shark, the lower caudal lobe (measured along it9 

 anterior edge) is about two-fifths as long as the 

 upper lobe; and the upper lobe is noticeably 

 slender toward its tip. The pectorals are about 

 as long (from origin to tip) as the distance from 



the tip of the snout to the level of the first pair of 

 gill openings, usually narrower, relatively, than 

 in the brown shark, and sometimes more definitely 

 sickle-shaped. 



The upper teeth are broadly triangular; nearly 

 erect toward the center of the mouth but weakly 

 oblique toward its corners; their inner margins 

 are nearly straight, the outer margins increasingly 

 concave outward along the jaw. The lower 

 teeth are erect, symmetrical, with narrow cusp on 

 a broadly expanded base. Both the upper teeth 

 and the lower are serrate along the edges, the 

 lower the more finely so. 



Color. — All the fresh caught specimens we have 

 seen have been bluish or leaden gray on the back 



