Fishes of the Western North Atlantic 485 



Color. Deep chocolate brown, darkest (almost black) below and on fins generally; 

 inner edge of anterior part of upper eyelid densely pigmented with dark brown or blackish. 



Size. Reported by fishermen as growing to about ^V-i feet, but adults average only 

 about 2 to 2V2 feet, the maximum length of which we find definite record being only about 

 33 inches (829 mm.). Females average larger than males, at least in Greenland waters. 



Developmental Stages. Presumably ovoviviparous like Squalus, but the early devel- 

 opmental stages have not been described, although embryos have been reported repeatedly. 



Habits. Captures of the Black Dogfish in West Greenland waters range from close 

 to the surface through the ice in winter down to 900 meters at least. Along the Nova 

 Scotian Banks they are most often taken at 200 to 300 fathoms and seldom shoaler than 

 150 fathoms, often in company with Centroscymnus coelolepis (p. 498). Although no 

 regular hook and line fishery is operated there at a greater depth, there is no reason to doubt 

 that they occur as deep in those waters as oflf Greenland (see above). Records for Icelandic 

 waters (perhaps the chief center of abundance) are mainly from about 500 to about 900 

 meters; they are recorded down to 1,100 meters oflF the Faroes, to 1,495 nieters off north- 

 west Africa, if the reports of the captures there are well founded (see footnote 5, p. 485). 



This, in short, is a deep-water species, normally approaching the surface only in 

 Arctic latitudes and at the coldest, or perhaps darkest, season. The fact that a trawl haul 

 on the south slope of the Davis Strait ridge (in water of 3.12° C.) yielded 42 specimens, 

 while another just north of the ridge took none (from water of 2.47°) is suggestive evi- 

 dence that it is an inhabitant of Atlantic and not of truly polar waters. 



Nothing is known of its life history other than that it bites the hook freely. Cephalo- 

 pods, pelagic crustaceans, and medusae (Atolla) have been found in its stomach, and 

 females containing embryos up to 124 mm. in length have been taken in West Greenland 

 waters in February. The fact that their skins are provided with minute, deeply pigmented 

 papillae, resembling the luminous organs of the brightly luminescent Isistius brasiliensis 

 (p. 512), suggests that C. fabricii also emits light, although it has not actually been seen to 

 do this so far as we know. 



Relation to Man. The Black Dogfish is of no commercial value, hence most of those 

 caught are thrown back. 



Range. Both sides of the North Atlantic, chiefly in depths greater than 150 fathoms; 

 Iceland (where most plentiful); Faroe-Shetland Channel and Faroe Bank in the east; 

 also reported from Arguin Bank oflF Cape Blanco, Northwest Africa;* Davis Strait; W^est 

 Greenland slopes and outer parts of the offshore fishing grounds in the west, from the 

 Grand Banks of Newfoundland to Georges Bank. 



Occurrence in the Western Atlantic. To the north the Black Dogfish is at least toler- 

 ably common in southwestern Greenland waters, both in the fjords and on the offshore 

 fishing banks; in the southern part of Davis Strait, and northward to the ridge that con- 



5. Doubt has been expressed as to the actual identity of the specimen from this locality reported by Vaillant (Exped. 

 Sci. "TravaiUeur" and "Talisman," Poiss., 1888: 72), since it was not only very small (175 mm.) but in a bad 

 state of preservation. 



