Fishes of the Western North Atlantic 327 



their leaf-like blades nearly horizontal with usually 3 (sometimes 5) low keels separated 

 by shallow valleys, their edges with 3 or 5 sharp teeth, the median considerably the 

 longest. 



Head a little more than y^ of total length. Snout rather thin-tipped, narrow-ovoid, 

 its length in front of a line connecting outer ends of nostrils % to % as great as distance 

 between inner ends of latter, its length in front of mouth about i V^ times as great as from 

 front of latter to origin of pectoral. Eye approximately circular, its diameter about % as 

 great as length of snout in front of mouth, or about % as long as ist gill opening, its mid- 

 point about opposite front of mouth. First gill opening about % times as long as diameter 

 of eye, the 3rd slightly longest, 5th a little the shortest, evenly spaced, the 4th above origin 

 of pectoral. Nostrils strongly oblique, the inner corners nearer to front of mouth than to 

 tip of snout by a distance equal to about V2 the diameter of eye, the anterior margins 

 slightly sinuous and expanded near inner end as a prominent triangular lobe with narrowly 

 rounded tip. Mouth broad-ovoid, about 1.7 times as broad as high in young specimens, but 

 1.5 times in larger. 



Teeth '^or u— n>r2— i2ori3 . yppers broadly triangular, their edges serrate, most coarsely 

 so on outer side of base, their inner margins straight near center of mouth but weakly con- 

 vex along outer part of jaw, the outer margins deeply notched and increasingly oblique 

 along the jaw, the outermost teeth very strongly so; lowers with slender cusps and broad 

 bases, erect in sides of jaw as well as in front, more finely serrate than uppers; one or two 

 very small erect teeth at symphysis in upper jaw, and one at symphysis in lower; outer- 

 most 2 or 3 teeth also very small in upper jaw, and with very short cusps in lower. 



Origin of ist dorsal over or slightly behind inner corner of pectoral, its anterior mar- 

 gin moderately convex in young but only slightly so in larger specimens, the rear margin 

 nearly straight toward apex but concave toward base, the apex narrowly rounded in young 

 but subacute in adult, the free rear corner only moderately slender, about Vs as long as base; 

 its vertical height a little greater than length of snout in front of mouth and about 57% 

 as great as length of pectoral. Second dorsal a little more than V3 as long at base as ist 

 dorsal, its origin about opposite that of anal, its anterior margin convex in young but nearly 

 straight in adult, its posterior margin weakly concave, apex broadly rounded in young but 

 more narrowly so in adult, its free rear corner about as long as base. Caudal a little more 

 than V4 (27 to 28%) of total length, with slender, subacute tip, the lower anterior lobe 

 (expanded lower anterior corner) 40 to 45% as long as upper margin, each measured 

 from its respective precaudal pit, with moderately convex lower anterior margin (more 

 so in young than in adult), and subacute tip (but rounded in newborn). Anal a little longer 

 at base than 2nd dorsal, its anterior margin more convex, its posterior margin much more 

 deeply concave, its apex subacute, its free rear corner about as long as its base, with tip 

 extending slightly farther rearward than tip of 2nd dorsal and anterior to lower precaudal 

 pit by a distance % as long as base of anal or about twice as long as diameter of eye. Dis- 

 tance between origin of anal and tips of pelvics a little longer than base of anal. Pelvics 



