52 BULLETIN OF THE BUREAU OF FISHEKIES 



17. Black dogfish (Centroscylliumfabricii Reinhardt) 



Jordan and Evermann, 1S96-1900, p. 56. 

 Garman, 1913, p. 231. 



Description. — As pointed out elsewhere (p. 44), the notched margin of the 

 upper tail lobe distinguishes this rare shark at a glance from the spiny dogfish, 

 with which it agrees in the possession of a long pointed spine at the front edge of 

 each dorsal fin, the second being longer than the first. It differs further in that its 

 dorsal spines are deeply grooved on each side, whereas in the "dog' ' they are rounded ; 

 in the location of the ventral fins, the rear axils of which stand almost directly under 

 the front origin of the second dorsal instead of some distance in front of it; in its 

 small pectorals of rounded outline; in the structure of its teeth, each of which is 

 tridentate, with sharp points; in its broad rounded snout; and in its very dark color. 

 Like the spiny dogfish, it lacks an anal fin. 



Size.— The specimens so far described have ranged from 2^ to 3^2 feet in 

 length — that is, about the same size as the spiny dogfish. 



Color. — Uniform dark brown to black, below as well as above. 



General range. — Positive records for this shark are from Greenland, Iceland, 41 

 rather deep water off the outer banks, Grand to Georges, 42 off the Hebrides and 

 Faroes where two specimens were taken by the Norwegian fisheries steamer 

 Michael Sars in 400 to 600 fathoms, and from the North Atlantic (two specimens in 

 the British Museum). But since Tate-Regan 43 thinks a specimen that he examined 



Fig. 19. — Black dogfish (CentroscyUium fabricii). After Garman 



from the Falkland Islands is identical, while Goode and Bean (1896) tentatively 

 refer to it a young shark from the Gulf of Mexico, and the Japanese C. ritteri 

 seems hardly distinguishable, the black dogfish may prove to have a cosmopolitan 

 range in deep waters. 



Occurrence in the Gulf of Maine.- — Evidently the black dogfish is very rare in 

 the Gidf of Maine, for it has so far been reported there only from Georges Bank, 

 from the slope off Browns in 200 fathoms, and vaguely from off Gloucester, which 

 might mean any of the fishing grounds between Cape Cod and Newfoundland. 

 However, it has been taken repeatedly on the offshore slopes of the Nova Scotian 

 Banks in 200 to 250 fathoms, whence a number were brought into the Bureau of 

 Fisheries by halibut fishermen many years ago. 44 Nothing is known of its habits. 



11 Sffimundsson. Videnskabelige Meddelelser fra Dansk naturhistorisk Forening i Kjftbenbaven, Bind 74, 1922, pp. 159-205. 



" According to Garman (1913), Greenland to New York. 



" Annals and Magazine of Natural History, Vol. II, Eighth Series, 1908, p. 49. London. 



<< For list of these specimens see Bean (1881, p. 116). 



