4-32 Memoir Sears Foundation for Marine Research 



but the 5th slightly concave anteriorly, their relative lengths increasing with growth, the 

 I St being only a little more than Mi as long as head in front of mouth or about 1.3 times 

 as long as diameter of eye in young, nearly % as long as head in front of mouth or 2.2 to 

 3.3 times as long as diameter of eye in medium-sized specimens, and nearly 90% as long 

 as head in front of mouth or 4.3 times as long as diameter of eye in largest measured (about 

 10 ft. 4 in. long); the 3rd gill opening very little longer than ist, the 5th only a little 

 shorter (about 84%) than ist, the two spaces between ist and 3rd about equally broad, 

 but those between 3rd and 5th much narrower, the 4th gill opening about over origin of 

 pectoral. Nostril approximately transverse. Mouth about ^o as long as broad. No trace of 

 lower or upper labial furrows, although there may be wrinkles at corners of mouth when 

 the latter is closed. 



Xeeth ■ 17— 2 or 3— 17 — (.j^gjj. edges reg;ularly and moderately coarsely serrate from 



16 or 17 — 1 to 3 — 16 or 17' o o ^ ^J J 



tip to base, except for the outermost i or 2, which are nearly or quite smooth ; upper teeth 

 triangular, on expanded bases, the ist tooth erect, symmetrical, but the subsequent upper 

 teeth increasingly oblique toward corners of mouth, their outer margins increasingly 

 notched, inner margins concave toward base except along outer Vs of jaw where they are 

 evenly and rather strongly convex; 2nd to lOth or nth upper teeth considerably the larg- 

 est and the outermost 2 to 3 very short; lower teeth similar to uppers, except perhaps a 

 little narrower and with inner edges along outer Ms of jaw nearly straight instead of con- 

 vex; 2 or 3 minute teeth at symphysis in upper jaw, and i to 3 in lower. 



First dorsal narrower toward apex and more sloping than in diplana or zygaena, a 

 perpendicular from its apex falling posterior to its rear tip in young specimens but a little 

 anterior to its tip in large, its origin about over midpoint of inner margin of pectoral, its 

 vertical height about V2 as great as length of head, the anterior margin moderately convex 

 toward apex but perhaps less so in adult than in young, the posterior margin deeply con- 

 cave in young but less so in adult, its free rear corner comparatively broad and only about 

 1/4 as long as base both in young and old (more than Y^ as long as base in diplana) ; the mid- 

 point of base about 1.8 times as far from origin of pelvics as from axil of pectoral in young. 

 Second dorsal at base averaging a little less than V2 as long as ist and about Y^ as high, its 

 origin a little anterior to midpoint of base of anal, its anterior margin moderately convex, 

 posterior margin very deeply concave in subangular outline (much more deeply so than 

 in either diplana or zygaena), apex rounded, its free rear corner about as long as the base 

 (much longer, relatively, in the diplana-zy gaena group). Caudal a little less than Yz (29 

 to 31%) of total length, its upper margin weakly convex in young and even less so in 

 adult, the terminal sector about % of the fin, with narrow tip and rather deeply concave 

 lower posterior margin, the lower lobe a little more than Vs (35 to 42%) as long as upper, 

 slender, with very narrowly rounded apex, its lower anterior margin rather strongly con- 

 vex in young but weakly so in adult, its posterior margin nearly straight; the re-entrant 

 contour (included between the 2 lobes) with rounded corner, a little less than a right angle. 

 Distance from origin of caudal to tip of anal a little more than Yi as long as base of latter. 



