240 THE PLAGIOSTOMIA. 



fin reaching a vertical from the origin of the subcaudal ; caudals about as deep as 

 long; subcaudal lobe nearly as deep as long, reaching a notch in front of the 

 terminal; pectorals little longer than wide. 



Total length 53.54 inches (136 cm.) of which the tail from the vent is one 

 third; head or depth equal three sixteenths of the length to base of supracaudal; 

 eye nearly one tenth, and snout to eye about two fifths of the head in front of the 

 gill opening. 



Brown; edges of fins darker. 



Sagami Sea, Japan. 



SOMNIOSUS. 



Somniosus Lesueur, 1818, Journ. Acad. nat. sci. Phil., 1, p. 222. 

 Laemargus Muller & Henle, 1837, Sitzb. Akad. wiss. Berlin, p. 116. 

 Scymnus (Laemargus) Muller & Henle, 1841, Plagios., p. 93. 

 Rhinoscymnus & Somniosus Gill, 1864, Proc. Acad. nat. sci. Phil., p. 264. 



Snout moderate, nostrils near the end. Caudal short and deep, other fins 

 small; the two dorsals without a fin spine; no anal fin. Mouth transverse, with 

 a deep straight groove across each angle, and with labial folds. Upper teeth 

 pointed, raptorial, several series in function, lower broader, sectorial with the 

 cusp directed obliquely outward, presenting the inner edge of each tooth toward 

 the upper teeth, and with a notch on the outer edge at the base. Spiracles 

 medium, behind the eye and slightly above its level. Tubercles small, uniform. 

 Gill openings narrow, hardly extending above the level of the pectorals. Two 

 species known, from the Arctic and North temperate seas. 



Dorsal origin about midway from pectorals to ventrals 



near the middle of the total length . . . brevipinna (page 240) 

 Dorsal origin near the pectorals about midway 



from the end of the snout to the caudal fin . microcephalus (page 241) 



Somniosus brevipinna. 



Plate 15, fig. 1-3. 



Somniosus brevipinna Lesueur, 1818, Journ. Acad. nat. sci. Phil., 1, p. 222, pi.; Bory, 1829, Diet. 



class, hist, nat., 15, p. 597; Storer, 1839, Report fishes, p. 189. 

 Scymnus micropterus Valenciennes, 1832, Nouv. ann. mus., 1, p. 454, pi. 20. 

 Scymnus brevipinna De Kay, 1842, N. Y. fish., p. 361, pi. 61, f. 202; Storer, 1867, Mass. fish, p. 259, pi. 



38, f. 2. 

 Leiodon echinatum Wood, 1846, Proc. Bost. soc. nat. hist., 2, p. 174. 

 Laemargus brevipinna Moreau, 1881, Poiss. France, 1, p. 361. 



Laemargus rostratus Helbing, 1904, Nova acta K. Leop.-Carol. akad. naturf., 82, pi. 9, f. A. 

 Somniosus microcephalus Regan, 1908, Ann. mag. nat. hist., ser. 8, 2, p. 54. 



