CENTROSCYMNUS. 203 



with a slender pointed broader based cusp; lower teeth broader, oblique, with 

 the inner or cutting edge convex and serrated, ending in a sharp smooth-edged 

 cusp at its outward extremity. Spiracles moderate, semilunate, distant one 

 and a half times their diameter from the orbit. Gill openings small, first about 

 one third the length of the orbit, hindmost nearly twice as wide as the first, 

 much wider than the fourth, in front of the pectoral. First dorsal reaching 

 Uttle behind the middle of the total length; spine little backward from the outer 

 angle of the pectoral; base including the spine equal four fifths of the length of 

 the outer edge of the pectoral, or two fifths of the distance from the base of the 

 first dorsal to the spine of the second; exposed portion of the spine short; upper 

 angle of fin rounded, hind angle produced, acute. Second dorsal as high and 

 four fifths as long as the first, similar in shape, length of base three fifths of the 

 distance from the caudal, spine one third exposed. Pectorals wide with a very 

 long acuminate inner angle, otherwise the hind margin is slightly concave. 

 One of the pectorals on the specimen described appears abnormal in that it is 

 subtruncate on the hind margin and lacks the acute angled extremity, which on 

 the normal fin reaches behind the spine of the first dorsal. Ventrals reaching 

 below the spine of the second dorsal, concave on the hind margin, acute in the 

 ends; claspers short, ends slender and pointed with a short slender spine a 

 little distance from the end on the outer side. Caudal with a well developed 

 subcaudal lobe. Scales somewhat rough, with five to nine converging keels or 

 striae on those of the head and shoulders; farther back the apices are smooth, 

 from wear, and the remains of the striae surround the base. Total length 345, 

 body 22^, snout to dorsal 13, snout to pectoral 8, snout to mouth 4, and caudal 

 fins 7 inches. 



Back and flanks brownish, lower surfaces white, a white border on the 

 fins and the gill covers. 



Lat. 35° N.; Lon. 139° 30' E., in 400 fathoms. Alan Owston. 



Centroscymnus. 



Centroscymnus Bocage & Capello, 1864, Diag. fam. Squal., p. 3 extra; Proc. Zobl. soc. London, p. 263; 

 1866, Plagios., p. 29. 



Body subfusiform, slightly compressed. Nostrils oblique, distinct from 

 the mouth cavity. Eye large, without nictitating folds. Mouth transverse, 

 slightly curved, with a deep groove and with labial folds at each angle. Teeth 

 dissimilar; upper raptorial, small, lanceolate, in three groups, the middle one of 

 which is outside (in front) of the lower jaws; lower teeth sectorial, broad, with 



