Fishes of the Western North Atlantic 413 



tance about twice as long as diameter of eye, and one connecting the corners of the 

 hammer passes a little posterior to the corners of the mouth in very small specimens but 

 a little anterior to them in larger, an alteration that results from an increase in the breadth 

 of the hammer relative to its length with growth, such as takes place in tudes also. 

 Mucous pores on lower side of head in midline cover a trapezoidal area (Fig. 80). Eye 

 a little broader than high, much smaller than in the diplana-zygaena group, its hori- 

 zontal diameter only about ^^ as long as head in front of mouth. Gill openings extending 

 ventrally and spaced nearly equally," the first Vs to V2 (41%) as long as head in front of 

 mouth and about 3.2 times as long as diameter of eye, the 3rd hardly longer than ist, and 

 5th very little shorter and about over origin of pectoral. Nostril transverse. Mouth 

 strongly arched, its breadth about 1.8 times its length, without definite labial furrow on 

 either jaw. 



Teeth |^^~|^ in specimen counted, smooth-edged and narrow-triangular on ex- 

 panded bases J uppers oblique, deeply notched outwardly and increasingly so toward 

 corners of mouth, the 4th or 5th to nth largest, the outermost 2 very low but still 

 with definite cuspj lower teeth with much narrower cusps, erect toward center of mouth 

 but somewhat oblique toward corners, the basal expansion somewhat swollen outwardly as 

 a rounded boss or obscure denticle on each side on median tooth and on a few teeth next 

 to the latter}' the 2nd to 7th or 8th longest, the outermost 2 very short, rounded, without 

 definite cusp (as in tiburo) ; 2 small symmetrical teeth at symphysis on upper jaw and 

 I on lower; i or 2 series of teeth functional in alternating rows along sides of upper jaw 

 and 2 to 3 rows along sides of lower. 



First dorsal at base a little less than V2 as long as head in front of origin of pec- 

 torals, its vertical height about i V2 times the base, erect, a perpendicular from its apex 

 falling through rear end of base or a little anterior to latter; its origin about over mid- 

 point of inner margin of pectoral, its anterior margin only slightly convex, rear margin 

 moderately concave toward base, apex subacute, its free rear corner about Y2 as long as 

 base, the midpoint of base only a little nearer to axil of pectoral than to origin of pelvics 

 with the rear tip about over the latter. Second dorsal at base a little more than Vs as long 

 as 1st and a little less than Vs as high vertically, its origin about over midpoint of base of 

 anal, its posterior margin moderately concave (much less deeply so than in tudes), and 

 apex narrowly rounded, its free rear corner only moderately slender, about i Yo times as 

 long as the base. Caudal a little less than Y3 (29%) of total length, the terminal sector 

 about Yi the length of fin and broadly triangular (considerably larger than in di-plana, 

 zygaena or iudes), with nearly straight lower posterior margin and subacute tip; the 

 lower lobe a little more than Vs (37%) as long as upper, with weakly convex anterior 

 margin, nearly straight posterior margin and subacute tip; the re-entrant contour (enclosed 



6. The g86-mm. specimen is asymmetrical as re^rds its gill slits, the 4.th and 5th coming close together at the lower 

 ends on one side of the head but evenly separated from end to end on the other. 



7. On the type specimen the first to fourth lower teeth on each side have these denticles more or less developed; in 

 the 8g6-mm. specimen the first right-hand and second left-hand lower teeth have one on each side, end the first 

 left tooth has one on one side only. 



