Fishes of the Western North Atlantic 417 



as its length to origin of pectorals, and a little more than 3 times its length at oculo-narial 

 prominence} anterior margin of head scalloped with a deep rounded depression opposite 

 nostril, a somewhat shallower indentation in the median line, and a still shallower sinuosity 

 midway between these two, also with a well marked groove running from the nostril in- 

 ward along anterior margin of head for about 40% of the distance toward the midline (a 

 little farther than this in zygaena). Distance from anterior corner of oculo-narial promi- 

 nence to anterior margin of eye about as long as diameter of eye (only about V2 to Vl that 

 long in zygaena) ; a line connecting outer ends of nostrils passes anterior to front of mouth 

 by a distance about as long as horizontal diameter of eye, one connecting centers of eyes 

 passes about through front of mouth, and one through the outer posterior corners of ham- 

 mer passes a little posterior to corners of mouth. Head (snout) in front of mouth a little 

 less than ^ as long as length to origin of pectorals. Rostral cartilage with a median oval 

 hole, the wings of the preorbital processes with an inwardly directed point on anterior 

 margin (this hole and point usually lacking in zygaena). Mucous pores in median sector 

 of oral side of head near its anterior margin cover a subrectangular or dumbbell-shaped 

 area (a subtriangular area in zygaena). Eye approximately circular, its diameter about 

 % as long as head in front of mouth. Gill openings noticeably longer than in zygaena, the 

 1st a little more than lYz ( i.6 to 1.7) times as long as diameter of eye, the 5th about 80% 

 as long as ist, their outlines evenly and moderately concave, the space between 4th and 5th 

 over origin of pectoral. Nostril nearly transverse. Mouth strongly arched, about V2 (49 

 to 56%) ashighasbroad. Labial furrows on lower jaw, about '^A to ^5 as long as horizontal 

 diameter of eye and concealed when mouth is closed, but none on upper jaw. 



Teeth '^ °' '^~° '° ^~'^ " ' I , triangular on expanded bases, the cusps smooth-edged, but 



15 or 16 — ^1 or 2 — 15 orlo'" r ' i o» 



the bases more or less wavy or fluted on some of the teeth; ist 3 upper teeth nearly sym- 

 metrical and erect, but subsequent teeth increasingly oblique toward corners of mouth, 

 their inner margins more nearly straight, the outer margins more and more deeply 

 notched; the ist tooth smaller than 2nd, the 15th and i6th very small; lower teeth with 

 somewhat narrower cusps than uppers, similarly oblique and notched outwardly in em- 

 bryos' and in small specimens generally, but with successive series tending to become more 

 erect and their cusps relatively narrower with growth, although there is considerable 

 variation in this respect." 



First dorsal erect, a perpendicular from the apex passing close behind rear end of 

 base, its vertical height about % (57 to 66%) as great as length of head to origin of pec- 

 torals with its length at base only a little less, its origin about over midpoint of inner 

 margin of pectoral, its anterior margin rather strongly convex toward apex, posterior mar- 



8. Personal communication from Stewart Springer. 



9. In the head of a Florida specimen, about 1,375 "^"i- lo^S (U.S. Nat. Mus., No. 1 10296, length calculated from 

 the breadth of the head), the first to eighth lower teeth are nearly erect with narrow triangular cusps, and the 

 lower teeth of the type specimen appear to have been similar. In another head of about the same size from Braz.l, 

 however, which is otherwise indistinguishable (Harv. Mus. Comp. Zool., No. 8+5), only the first and second lower 

 teeth are of this type, the third and subsequent teeth being increasingly oblique, and intermediate stages are shown 

 by other specimens. It is not yet known whether the variations in this respect are individual or racial. 



