2 1 8 Memoir Sears Foundation for Marine Research 



on trunk close-spaced, their blades only slightly raised, with 3 low ridges, their posterior 

 margins with 3 strong teeth, the median much the longest; the 2 or 3 rows along the dorsal 

 margin of the anterior half of the caudal larger, only weakly dentate and without ridges, 

 flanked on either hand by a single row of very much larger blade-like denticles, lanceolate 

 in shape, their inner margins with a deep notch, their tips directed outward and bounded 

 below by a narrow band of naked skin forming a noticeable crest, but grading rearward 

 into denticles of the usual size and shape. 



Head strongly flattened above. Snout thin, broadly rounded in front and slightly 

 narrowed opposite nostrils, its length in front of mouth about Vs of length of head to origin 

 of pectoral. Eye narrow-oval, its horizontal diameter a little more than Yo as long as 

 snout in front of mouth, with a weakly marked longitudinal fold below it. Spiracle oval, 

 its diameter about Yi as great as that of eye, behind the latter by a distance about Yz as 

 great as the horizontal diameter of eye, and a little below it. Gill openings concave ante- 

 riorly in outline, the 4th and 5th closest together, the ist and 2nd (slightly the longest) 

 about Ys as long as horizontal diameter of eye, the 5th (shortest) about % as long as ist; 

 the 5th above or a little posterior to origin of pectoral. Nostrils oblique, separated one from 

 the other by a distance equal to about % the length of snout in front of mouth, and sepa- 

 rated from mouth by a distance about Y2 that great, the anterior margin expanded as a low, 

 subtriangular lobe with rounded tip, the posterior margin not expanded. Mouth obtusely 

 ovate, about V2 as long as broad, with labial furrows extending a short distance inward 

 along both jaws. 



Teeth about ffEffj with slender median cusp, and a much smaller cusp on each side in 

 central part of mouth, but usually with 2, or even 3, lateral cusps on each side toward cor- 

 ners of mouth; 4 or 5 series functional in front of mouth, with 2 to 3 toward its corners 

 in upper jaw and 3 to 4 series in lower jaw. 



Dorsals small, similar in size and shape, quadrate, with weakly convex anterior mar- 

 gins, straight distal margins and subrectangular corners, their bases about as long as snout 

 in front of eye or a little shorter, their free lower margins about Y2 as long as their bases 

 or a little less; origin of ist dorsal over rear Ys of bases of pelvics, origin of 2nd dorsal 

 about over midpoint of base of anal. Caudal about Y-i of total length, and noticeably 

 narrow, its axis only very slightly raised, its tip squarely truncate posteriorly, its lower 

 anterior corner much more obtuse than a right angle, the subterminal notch scarcely 

 marked. Interspace between caudal and anal varying from about Y2 as long as base of anal 

 to almost as long as latter. Anal about twice as long at base as 2nd dorsal, Its rear tip a little 

 anterior to rear tip of latter, with nearly straight margins and rounded apex, its free basal 

 margin very short. Pelvics with broadly rounded apices and tapering, blunted tips, widely 

 divergent in adults but less so in smaller specimens, their inner edges joined and attached 

 to ventral surface of trunk for about Y2 their lengths posterior to cloaca, both in males and 

 in females. Pectoral with very broad base, nearly straight margins and broadly rounded 

 corners, about as broad as long, and about 3 times as large in area as ist dorsal. 



Color. Ground tint pale yellowish brown, strikingly marked along sides and back 



