FISHES OP THE GULF OF MAINE 53 



THE NURSE SHARKS. FAMILY SCYMNORHINID^ 



The nurse sharks, like the spiny dogfishes, lack anal fins, but there are no 

 spines in their dorsal fins and the teeth in the upper jaw are noticeably unlike those 

 in the lower. 



IS. Greenland shark {Somniosiis microcephalus Bloch and Schneider) 

 Nurse shark; Sleeper shark; Gurry shark; Ground shark 



Jordan and Evermann, 1896-1900, p. 57. 

 Garman, 1913, p. 241. 



Description. — The Greenland shark is notable for its very small dorsal fins, 

 without spines, the second being of about the same size as the first, and for small 

 pectorals hardly larger than the ventrals, coupled with the absence of an anal fin 

 and with a tail of more "fishlike" form than that of most other sharks except the 

 mackerel-shark tribe. Bearing these points in mind, particularly the absence of 

 anal fin and dorsal spines, it can not be confused with any shark common in our 

 Gulf. The location of the first dorsal — about midway between pectorals and 

 ventrals — is the most obvious "field mark" to distinguish it from the rare Echino- 

 rhinus hrucus (p. 55). We may note further that the Greenland shark is compara- 



FiG. 20. — Qreenland sbark iSomniosus Tnicroccphatus). After Garman 



tively stout shouldered, tapering thence toward the tail; that its snout is blunt and 

 rounded as Scoresby *^ represented it a century ago (many more recent figures of 

 it are caricatures in this respect) ; that the gill openings are short and located low 

 down on the sides of the neck; and that the teeth are unlike in the two jaws, being 

 narrow in the upper, and broad, square tipped, and notched at the outer corners in 

 the lower jaw. 



Size. — This is one of the larger sharks. It is said to grow to a maximum 

 length of 24 feet, but few, if any, actually reach such a size, 18 feet being unusual. 

 One 15 feet long has been taken in Cape Cod Bay; another of 133^ feet (now in the 

 Museum of Comparative Zoology) in Massachusetts Bay. Perhaps S to 12 feet 

 would be a fair average for adults; nor is this size exceeded often among the hundreds 

 annually caught about Iceland and Greenland. 



General range. — Arctic seas; south to Cape Cod in the western North Atlantic, 

 and to France in the eastern North Atlantic; to Oregon in the Pacific. It is the 

 object of a regular fishery in Greenland, Iceland, Norway, and Spitzbergen. 



Occurrence in the Gulf of Maine. — Although there is no reason to suppose that 

 the Greenland shark is ever common in our Gulf or appears there other than as a 



" An account of the Arctic Regions, and of the whale fishery, 1820, Vol. II, PI. XV, flgs. 3 and 4. 



