80 CAR0HARODON C ARCH ARIAS. 



The anal fin, two inches behind the second dorsal, is 

 two inches high, one and one-half inches wide at the 

 base, and two inches wide at the free extremity. 



The caudal fin is large and strong, lunate. The two 

 lobes are nearly of equal size, the upper lobe being- 

 twenty -three inches long, and the lower lobe eighteen 

 inches. The upper lobe has a notch in the posterior 

 edge near its end. The width of the caudal fin, in the 

 median line, is eight inches. Greatest width of lobes, 

 ten inches. Distance between extremities of the two 

 lobes is thirty inches. 



The caudal peduncle is ten inches long and carinated 

 on both sides ; the keel is thirteen inches long, ex- 

 tending an inch in front of the anal fin. There is no pit 

 at the root of the caudal. 



BRANCHIAL OPENINGS. 



The gill-openings, five in number, are lateral, anterior 

 to, and their lower extremities on a level with, the base 

 of the pectorals. The first and second are thirteen 

 inches long, and the other three are eleven and one-half 

 inches long. The last branchia on either side is close to 

 the base of the pectoral, and overlaps it an inch or one- 

 half of the branchial width. Gill-openings occupy a 

 horizontal space of nine and one : half inches above and 

 seven inches below. The inter-branchial space, sub-tho- 

 racic, is fifteen inches. No spiracles. 



In making a diagnosis of the species here represented, 

 I shall follow the general analysis given by Professors 

 Jordan and Gilbert, in their Synopsis of the Fishes of 

 North America, published under the direction of the 

 Smithsonian Institution in 1882. 



There are thirteen families in the order Squall (the 

 sharks ;) and, by analysis, it is found that the existence 

 of an anal fin, two dorsal fins without spines — the first 

 dorsal being anterior to the ventrals, — a caudal fin 



40 



