498 Memoir Sears Foundation for Marine Research 



average 3 to 2Y2 feet in length, the largest for which actual measurements are available 

 being about 44 inches long (1,117 mm.) ; see Study Material, p. 494. Twelve kilograms 

 (about 26^/^ pounds) is the only weight of which we find record. 



Developmental Stages. It is no doubt ovoviviparous. All that is known of its early 

 development is that gravid females have been taken with 1 3 to 16 embryos. 



Habits. This is strictly a deep-water shark, as noted below. Apparently it is also a 

 very sluggish one, for those caught in the Portuguese deep-water fishery have been de- 

 scribed as falling into the boat entirely inert. But this may be the result of the change in 

 pressure or in temperature to which they are subjected while being hauled in. Off the 

 American copst, this shark occurs mostly at temperatures of 5° to 6° C; between about 

 4° and 10° or 11° off Portugal; and at 12° to 13° in the Mediterranean. All that is known 

 of its food is that an argentine {Argentina silus) was found in one, suggesting a fish diet. 

 Nothing is known of its breeding habits, except for the number of embryos (see Develop- 

 mental Stages, p. 498). 



Relation to Man. This shark is considered worthless in American waters, but it has 

 been the object of a local deep-water fishery with long lines off Portugal in the past. 



Range. Both sides of the North Atlantic, chiefly in depths greater than 200 fathoms, 

 and recorded down to 1,487 fathoms (2,718 meters); taken off Cape Verde, Morocco, 

 Azores, Madeira, Portugal, Faroe Bank, and Iceland in the east, as well as in the western 

 part of the Mediterranean; offing of Nantucket to slopes of the Grand Banks in the west. 



Occurrence in the Western Atlantic. Positive records of this deep-water shark in the 

 western Atlantic are from the continental edge off Nantucket, from the deeper slopes of 

 Georges and the Nova Scotian Banks, and from the Grand Banks; a total of perhaps 15 to 

 20 specimens are recorded at depths ranging from 1 80 fathoms, which is the shoalest cap- 

 ture of it anywhere, down to 250 fathoms. No doubt, however, an old characterization of it 

 as abundant on the offshore banks at 200 fathoms^ or deeper presents its status much more 

 correctly than does the meager printed record, for fishermen, long-lining for halibut, take 

 odd specimens all over the halibut grounds in the deep gullies between the offshore banks, 

 usually at least one or two per trip. Since this is the only local type of fishery that is carried 

 on at a depth great enough to take them at all, it would not be astonishing if experimental 

 hook and line fishing on the still deeper slopes, down to 300 or 400 fathoms, were to yield 

 them as plentifully as was the case formerly off Portugal, where there is record of five or 

 six hauled in on a long line with 30 to 40 hooks (baited with fish) after a set of only two 

 hours.' As it is of no commercial value only an odd one is brought in as a curiosity. 



Synonyms and References: 



Centroscymnus coelolefis Bocage and Brito Capello, Proc. zool. Soc. Lond., 1864: 263, fig. 4; Diag. Famil. 

 Squalidae, 1864: 3; also same title in Mem. R. Acad. Lisboa, j, 1865: 3 (descr., Portugal); Poiss. Pla- 

 giost., 1866: 30, pi. 2, fig. 3 (Portugal, Madeira); Wright, Ann. Mag. nat. Hist., (4) 2, 1868: 426 



5. Goode and Bean, Bull. Essex. Inst. Salem, 11, 1879: 30. 



6. Wright, Ann. Mag. nat. Hist., (4) 2, 1868: 426. 



