36 



BLUE SHARK. 



effect of age, but is to be perceived in Sharks in the earliest 

 stage of their growth. 



The largest I have heard of, but not seen, was upwards of 

 fourteen feet long, but the more ordinary size is from six to 

 eight feet in length; the body round and slender, tapering 

 towards the tail. Head flat on the top, snout depressed, pro- 

 jecting; the mouth far beneath, well furnished with strong, flat, 

 triangular teeth, the points inclining inward, the edges serrated. 

 Nostrils a good distance from the mouth, and not lobed; gill 

 openings five, near the root of the pectoral fin. Skin but 

 slightly rough; pectoral fins large and long, although not pro- 

 portionally so much so as is represented in Lacepede's figure 

 of his smooth-toothed Blue Shark, vol. i., pi. 9, f . 1 ; and which 

 therefore, if correctly represented, will be an additional mark 

 of distinction between the two sj)ecies. These fins are placed 

 low on the body in all Sharks, and in the Blue Shark end in 

 a point. The ventrals small; the anterior border of the first 

 dorsal fin begins midway between the snout and root of the 

 tail; the second dorsal opposite the anal. The upper lobe of 

 the tail moderately long, with a notch, as in most Sharks, near 

 the end; at its root also, where it joins the body, a deep 

 depression, but I have known this wanting. The upper parts of 

 the body and fins blue, the belly white. 



INSIDE VIEW OF THE TEETH. 



UPPEK TEETH. 



