lyo Memoir Sears Foundation for Marine Research 



Trunk stout, somewhat compressed laterally, its dorsal profile strongly convex ante- 

 rior to I St dorsal, its depth opposite the latter about V^ its length to origin of caudal. 

 Caudal peduncle strongly compressed laterally, about i V2 times as high as thick, without 

 longitudinal lateral ridges or keels. A well marke_d precaudal pit above (Fig. 27 A) but 

 none below. Dermal denticles closely overlapping and very small, being only about 0.2 X 

 0.21 mm. in a 15-foot specimen, blades horizontal, usually with 3, sometimes with 5, low 

 keels, and as many rather short marginal teeth, the median largest; moderately long 

 pedicels. 



Head and snout together subconical, between Y^ and Y^ as long as trunk to origin 

 of caudal. Snout rounded at tip and very short, its length in front of mouth only about 

 Y4 to V5 the length of head. Eye circular, moderately large, its margin considerably ante- 

 rior to front of mouth, its diameter about Y2 as long as snout in front of mouth in small 

 specimens, but only about Ys that length in large. Spiracle pore-like, on same level as center 

 of eye and behind latter by a distance about Y2 as great as length of snout in front of mouth. 

 Gill openings terminating relatively high up on the sides of neck, noticeably short, the 

 longest only a little longer than diameter of eye in small specimens, but about twice as long 

 in large ones; ist to 4th evenly spaced, the lower ends of 4th and 5th close together over 

 origin of pectoral. Nostril transverse, considerably nearer to mouth than to tip of snout, its 

 anterior margin expanded in low, subtriangular contour. Mouth broadly rounded, about 

 twice as wide as high. Upper labial furrow reaching about Ys of distance to symphysis, the 

 lower furrow only about Y2 as long as upper and visible only when mouth is open. 



Teeth l^Ezi i^i specimen counted; similar in the 2 jaws, blade-like, subtriangular, 

 with single sharp-pointed cusp and smooth edges, the ist to 3rd uppers and ist and 2nd 

 lowers nearly symmetrical, but successive teeth increasingly oblique, with their outer 

 margins increasingly deeply concave; the 3rd upper tooth only about % as high as ist 

 and 2nd, or as 4th to lOth; ist lower tooth also very small; lOth or nth and subsequent 

 teeth in each jaw decreasing successively in size toward corners of mouth, the outermost 

 minute in lower jaw; i and sometimes 2 rows functional in front of mouth, 2 rows toward 

 corners.^*" 



Origin of ist dorsal only slightly behind inner corner of pectoral, its rear tip anterior 

 to origin of pelvics by a distance about as great as length of snout in front of mouth, its 

 anterior margin moderately convex, the apex rounded, the posterior margin only slightly 

 concave basally, its free rear tip only about V5 as long as its base, its vertical height less 

 than V2 as great as length of pectoral. Second dorsal only about Ys as long as ist dorsal 

 along anterior margin, its origin much nearer to origin of caudal than to rear end of base 

 of 1st dorsal, its apex rounded, its rear tip slender, elongate, nearly or quite twice as long 

 as its base, the rear end of its base about over origin of anal, or a little anterior to latter. 



16. According to Moreau (Hist. Nat. Poiss. France, z, 1881 : 288) the first small tooth in the lower jaw is lost with 

 age; also, in the upper jaw there may be a minute first tooth in small specimens, which is similarly lost with 

 age. But the specimens we have seen lack this small median upper tooth, the first pair of large teeth being close 

 together at the upper symphysis. 



