514 Memoir Sears Foundation for Marine Research 



Echinorhinus brucus Fowler, Occ. Pap. Bishop Mus., 8 (7), 1923: 375 (Honolulu); not Squalus brucus 

 Bonnaterre, 1788.' 



Genus Somniosus Lesueur, 1 8 1 8 



Somniosus Lesueur, J. Acad. nat. Sci. Philad., i, 1818: 222; type species, S. brevipjnna Lesueur, Massachusetts, 

 monotypic. 



Generic Synonyms: 



Squalus Gunnerus, Drontheim Gesellsch. Schr. Leipzig, 2, 1776: 299; for S. carcharias Gunnerus; not Squalus 



Linnaeus, 1758. 

 Acanthorhinus (in part) Blainville, Bull. Soc. philom. Paris, 1816: 121: for 5. nortvegianus Blainville.^ 

 Scymnus (in part) Fleming, Hist. Brit. Anim., 1828: 166, for S. borealis Fleming, equals Squalus borealis 



Scoresby, 18 20; not Scymnus Cuvier, 181 7. 

 Laemargus (subgenus) Muller and Henle, Plagiost., 1 841: 93; type species, 5. borealis Fleming, 1828, equals 



Squalus borealis Scoresby, I 8 20, Spitzbergen. 

 Leiodon Wood, Proc. Boston Soc. nat. Hist., 2, 1846: 174; type species, S. echtnatum Wood, monotypic. 

 Dalatias (Somniosus) Gray, List Fish. Brit. Mus., 7, 1851 : 76, for Scymnus (Laemargus) borealis Muller and 



Henle, 1841, equals Squalus borealis Scoresby, 1820; not Dalatias Rafinesque, 1810. 

 Scimnus Vzn Beneden, Bull. Acad. Sci. Roy. Bruxelles, 20 (2), 1853: 258; emended spelling for Scymnus. 

 Rhinoscymnus Gill, Proc. Acad. nat. Sci. Philad., 1864: 264, footnote 5; type species, Scymnus rostratus Risso, 



1826, monotypic. 



Generic Characters. Dalatiidae without dorsal fin spines 5 snout in front of mouth 

 much shorter than from front of mouth to origin of pectorals; midline of back with a 

 faint dermal ridge; caudal peduncle with faint lateral ridges, at least in some cases, but 

 without precaudal pits; labial furrows and a pit prolonged rearward from corner of mouth ; 

 teeth widely dissimilar in the two jaws; the uppers slender, conical, widely spaced; the 

 lowers quadrate, each overlapping the next outermost, the cusps smooth edged and so 

 oblique that their inner margins form a continuous cutting edge, much as in Squalus and in 

 Centroscymnus; dermal denticles conical to thorn-like, curved rearward; rear end of base 

 of 1st dorsal far anterior to origin of pelvics; 2nd dorsal over or a little posterior to rear 

 end of bases of pelvics; 2nd dorsal only about as large as ist dorsal, but pelvics consider- 

 ably larger; interspace between ist and 2nd dorsals longer than between pelvics and 

 caudal; caudal very wide relative to its length, its lower anterior corner forming a more 

 or less definite lobe, its subterminal margin notched; pectorals with broadly rounded cor- 

 ners; with or without functional luminous organs (see p. 516). Development ovovi- 

 viparous in one species, perhaps oviparous in another. Characters otherwise those of the 

 family. 



Range. Arctic Atlantic (including White Sea) south to North Sea, Portugal, Mediter- 

 ranean and Cape Cod; Bering Sea, in North Pacific, south to Japan, southeastern Alaska, 

 and occasionally southern California; also Antarctic (Maquarie Island). 



9. Fowler and Ball (Bull. Bishop Mus., i6, 1926: 5, footnote) point out that specimens in the Bishop Museum on 

 which this record was based are actually /. brasiliensis. 



I. This is a nomen nudem, see footnote 37, p. 523. 



