276 BULLETIN 10 0, UNITED STATES NATIONAL MUSEUM 



Gill openings narrow, liardly extend above level of pectorals. Spir- 

 acles moderate, behind and slightly above level of eye. Tubercles 

 small, uniform. 



Two species in Arctic and North temperate seas. Oviparous, 

 though the eggs without a horny capsule and deposited on the sea 

 bottom. 



SOMNIOSUS MICROCEPHALUS (Schneider) 



Squalus microcephalus Schneidee, Syst. loLth. Bloch, p. 135, 1801 (type local- 

 ity: Glacial Sea). 

 Acanthorhinns microcephalns Blainville, Bull. Soc. Philomath. Paris, vol. 8, 



p. 121, 1816 (name only). 

 Somniostis microcephalus Jordan and Snyder, Annot. Zool. Japon., vol. 3, p. 



129, 1901 (Tokyo).— Jordan and Fowlee, Proc. U. S. Nat. Mus., vol. 26, 



p. 638, 1903 (Tokyo).— Regan, Ann. Mag. Nat. Hist, ser. 8, vol. 2, p. 54, 



1908 (Arctic Seas south to Japan, Cape Cod and France). — Gaeman, Mem. 



Mus. Comp. Zool., vol. 36, p. 241, pi. 15, figs. 4-6, 1913 (Massachusetts).— 



Fowler, Proc. 4th (1929) Pacific Sci. Congr., Java, p. 497, 1930 (reference).— 



SoLDATOw and Lindbeeg, Bull. Pacific Sci. Fisher. Inst., vol. 5, p. 17, 1930 



(Far East Seas). 

 Acanthorhinns norivegiamis Blainville, Bull. Soc. Philomath. Paris, vol. 8, 



p. 121, 1816 (name only), 

 Squalus norvegianus Blainville, Faune Frangaise, Poissons, p. 61, 1825 (Mers 



du Nord ; on Haa-sJcicrding Gunner, Act. Nidrosiana Trondhjem, vol. 2, p. 



330, pis. 10-11, 1763) . 

 Somniosus irevipinna Lestteur, Journ. Acad. Nat. Sci. Philadelphia, vol. 1, 



p. 222, pi., 1818 (type locality: Near ]\Ia rblehead, Mass.). — Gaeman, Mem. 



Mus. Comp. Zool., vol. 36, p. 240, pi. 15, figs. 1-3, 1913 (Sagami Sea, Japan). 

 Squalus borealis Scoeesby, Arctic regions, vol. 1, p. 538, pi. 15, figs. 3-5, 1820 



(type locality: Spitzbergeu Sea). 

 Scymnus rostratus Risso, Hist. Nat. Europe m(^rid., Poissons, vol. 3, p. 138, pi. 



3, fig. 7, 1826 (type locality: Nice). 

 Scymnus gtinneri Thibnemann, Lehrb. Zoologie, p. 1828 (on Gunner). 

 Scymnus glacialis Fabee, Nat. Fische Islands, p. 23, 1829 (type locality: Iceland). 

 Scymnus micropterus Valenciennes, Nouv. Ann. Mus. Hist. Nat. Paris, vol. 1, 



p. 458, pi. 20, 1832 (type locality: "Habitat in Oceano boreali"). 

 Leiodon ecMnatum Wood, Proc. Boston Soc. Nat. Hist., vol. 2, p. 174, 1846 (type 



locality: "Taken about 80 miles east of Portland"). 

 Squalus norvegicus Geay, Cat. Fish. Gronow, p. 8, 1854 (type locality : Biorn 



Island, Norwegian Sea). 



Depth 5% to 6% to subcaudal origin; head 4% to 4%. Snout 

 214 to 2% in head; orbit 9 to lli/^, 3V& to 4^^ in snout; mouth width 

 subequal with snout, with groove at angle extending back or little be- 

 hind spiracle; teeth in TO rows above, narrower than lower, 54 rows 

 below, roots variably slender or elongate to short and wide in lower ; 

 nostrils about first third in snout; preoral length 2l^ to 2i/4 in head; 

 interorbital rather elevated. Gill openings equidistant, 2% to 3 in 

 snout length, upper edge of last before pectoral origin. Spiracle 

 nearly or quite equals orbit, superior, distant from upper hind orbital 

 edge space equal to 2% to 3 in snout length. 



