18 



FISHERY BULLETIN OF THE FISH AND WILDLIFE SERVICE 



21. Lower teeth erect, triangular, their edges serrate Dalatias licha, p. 55 



Lower teeth quadrate, the cusp directed outward, forming a nearly continuous horizontal cutting edge; their outer 



margins deeply notched, the edges smooth . 22 



22. Dermal denticles rounded, overlapping, scale-like, entirely concealing the skin (fig. 20) ; each dorsal fin is preceded 



by a short spine, embedded nearly to its tip in the skin, but recognizable by touch Portuguese shark, p. 52 



Dermal denticles conical, only moderately close set, the skin visible between them; dorsal fins not preceded by 



spines Greenland shark, p. 53 



Note. — Not yet known from the Gulf of Maine though reported from Marthas Vineyard. 



THE SAND SHARKS. FAMILY CARCHARIIDAE 



Outstanding characteristics of the sand sharks 

 are that they have an anal fin ; the two dorsal fins 

 are without spines and are nearly equal in size ; the 

 rear end of the base of the first dorsal is over or in 

 front of the origin of the pelvic fins; the anal fin is 

 about as large as the dorsals; the upper lobe of the 

 caudal fin is much longer than the lower, but 

 occupies not more than one-third of the total length 

 of the fish; there are no lateral keels on the caudal 

 peduncle; the fifth gill openings are farther forward 

 than the origins of the pectoral fins; and the teeth 

 are slender and sharp-pointed. 



Sand shark Carcharias taurus Rafinesque 1810 



Dogfish shark; Ground shark 



Bigelow and Schroeder, 1948, p. 100. 

 Garman, 1913, pi. 6, figs. 1-3. 



Description. — The large size of the second dorsal 

 fin, and of the anal as well (which is about equal to 

 the first dorsal instead of much smaller) is of itself 

 enough to distinguish this species from all other 



Gulf of Maine sharks. The fact that the first dorsal 

 fin is located but little in front of the pelvics, and 

 that the trunk seems crowded with fins of equal 

 size, is a useful field mark. We may also point out 

 that the pectoral fins are not much larger than the 

 other fins — triangular rather than sickle-shaped; 

 that the upper lobe of the tail is nearly one-third 

 as long as head and body together and notched 

 near its tip, with the lower lobe about one-third 

 as long as the upper lobe; and that the head is 

 flat above, the snout short, conical with rather 

 sharp tip. The teeth also (alike in the two jaws) 

 are diagnostic, being long, narrow, sharp-pointed, 

 and smooth-edged, with one (rarely two) small 

 spurs ("denticles") on either side near the base. 



Size. — Most of the sand sharks that are caught 

 in the northern part of their American range, from 

 Delaware Bay to Cape Cod, are immature, of 

 perhaps 4 to 6 feet. But adults up to 8 or 9 feet 

 long are reported there from time to time, espe- 

 cially from the vicinity of Nantucket, where a 

 commercial shark fishery yielded many of them in 



Figure 4. — Sand shark (Carcharias taurus), about 40 inches long, Cape Cod; and upper and lower teeth from front part 

 of mouth of a larger specimen from New Jersey, about natural size. From Bigelow and Schroeder. Drawings by 

 E. N. Fischer. 



