1908.] NATURAL SCIENCES OF PHILADELPHIA. 71 



DESCRIPTION OF A NEW SPECIES OF SQUALOID SHARK FROM JAPAN. 



BY CHIYOMATSU ISHIKAWA, PH.D. 



Squalus japonious Ishikawa, new species. 



Acanthias vulgaris Schlegel, Fauna Japonica, Poisson, p. 304, PI. 135, 1850; 

 Acanthias vulgaris, Ishikawa, Prelim. Cat., p. 61, 1897. Not of Risso. 



Body elongate, slender, tail moderately tapering behind. Head 

 rather narrow; snout produced, pointed, upper surface flattened; 

 nostrils nearer mouth than tip of snout, nearly midway between angle 

 of mouth and tip of snout. Nasal flaps normally formed. 



Eyes large, lateral, situated nearer first gill-opening than end of snout. 

 Length of eyelid a little less than half distance from its anterior angle 

 to tip of snout. Spiracles large, closely posterior to and little above 

 eye, vertical diameter of spiracle slightly over one-third length of eye. 

 Spiracular valve not very fleshy. Narrow groove between posterior 

 angle of eye and lower border of spiracle. 



Mouth moderate, slightly curved, situated at about three-fifths 

 distance from tip of snout to level of first gill-opening. Upper Hp well 

 developed, lower closely attached to teeth within. Oral groove nearly 

 straight, deep. 



Teeth of upper jaw smaller than those of lower, and somewhat more 

 erect. Gill-openings in front of base of pectoral, and slightly above, 

 fourth and fifth gill-slits somewhat nearer together than preceding ones. 



First dorsal nearer to pectoral than to ventral, its origin somewhat 

 in advance of inner posterior angle of pectoral, midway between tip of 

 snout and origin of second dorsal; first dorsal spine slightly less than 

 height of fin ; posterior border somewhat emarginate and slightly pro- 

 duced. Second dorsal about midway between ventral and caudal, 

 smaller, posterior margin rather deeply emarginate, lower lobe moder- 

 ately produced ; spine as long as fin and longer than that of first. Both 

 spines triangular, without any lateral groove, but hinder margin 

 slightly hollowed out. Pectorals large, but shorter than head, reaching 

 beyond origin of first dorsal, its hinder margin moderately emarginate. 

 Ventrals midway between first and second dorsals; caudal lobes well 

 developed. Upper caudal groove triangular and ver}^ distinct; lower 

 rather inconspicuous. 



Scales very minute, closely set; each with a median keel which ends 



