312 Memoir Sears Foundation for Marine Research 



only slightly compressed laterally, about % as high as thick. Upper precaudal pit strongly 

 marked as a subtriangular depression, its concavity rearward, but no lower precaudal pit. 

 Dermal denticles comparatively large (average about 0.4 x 0.6 mm. in 2,490-mm. speci- 

 men), mostly overlapping, with 3 or 5 ridges, the median ridge and the pair next to it high, 

 sharp-topped and separated by deep furrows, the posterior margins with prominent teeth 

 opposite the 3 primary ridges, the median a little the longest, with or without small teeth 

 opposite the outermost pair of ridges on such of the denticles as have the latter; pedicels 

 moderately broad, as are the basal plates. 



Head moderately flattened above, its length to 5th gill opening a little less than V4 

 of total length, its breadth opposite corners of mouth a little less than % its length. Snout 

 very broadly and evenly rounded, its length in front of a line connecting outer ends of 

 nostrils only about Yo as great as distance between inner ends of latter, its length in front 

 of mouth equal to distance between nostrils, or to about V4 the length of the head. Eye 

 oval, noticeably small, its horizontal diameter a little less than V3 as long as distance be- 

 tween nostrils, and only about V2 to % as long as ist gill opening. Gill openings all of 

 very nearly equal lengths, about i V2 to 2 times as long as diameter of eye, evenly spaced, 

 the 1st about perpendicular, but the 3rd to 5th increasingly oblique, the 4th above origin of 

 pectoral. Nostril moderately oblique, its inner end a little nearer to front of mouth than 

 to tip of snout, its anterior margin expanded as a triangular lobe about as long as broad, the 

 distance between inner ends of nostrils about V2 to % as great as breadth of mouth and 

 about % as great between their outer ends. Mouth broadly rounded and moderately 

 arched, its height slightly more than V2 as great as its breadth (51 to 60% in specimens 

 examined), occupying about % of breadth of head. Upper labial furrow extending out- 

 ward nearly at right angles to upper jaw as a deep groove for a distance about V3 as long 

 as horizontal diameter of eye; no furrow on lower jaw. 



Teeth i3o'/j7^'3°i."^" 14 ' ^^'■^ ^^T sharp cutting edges; upper teeth with narrow trian- 

 gular cusps and broad bases, symmetrical and erect in central part of jaw but increas- 

 ingly oblique toward its corners, the outer margins increasingly notched with the outer- 

 most deeply so, the edges of cusps smooth but edges of basal sectors with moderately 

 fine, irregularly rounded serrations, except for the smooth small teeth at the sym- 

 physis and near the corners of the jaw; lower teeth similar in general to uppers, except 

 somewhat more slender and more erect, the bases, as well as cusps, smooth-edged, except 

 near the corners of the jaw where they are somewhat wavy; i to 3 minute, smooth-edged 

 teeth at symphysis in upper jaw and 3 in lower; outermost 3 or 4 teeth in each jaw very 

 small; i row functional, or 2 rows in places. 



First dorsal low relative to its length, its anterior margin about 1.25 times as long as its 

 base, its vertical height slightly less than V2 as great as length of pectoral, its origin a little 

 posterior to corner of pectoral, its anterior margin nearly straight, apex narrowly rounded, 

 posterior margin nearly straight toward apex but moderately concave basally, its free rear 

 corner about ^o as long as the base. Second dorsal similar to ist dorsal in shape, nearly as 



