1 1 6 Memoir Sears Foundation for Marine Research 



or knobs that vary in distinctness from specimen to specimen. Gill openings noticeably 

 small; first to fourth a little less than half as long as breadth of closed mouth, fifth about 

 75 "/o as long as first to fourth; distance between inner ends of gill openings of fifth 

 pair a little smaller than distance between spiracles. Nostrils approximately transverse, 

 their inner ends reaching the deep furrow that surrounds mouth, thus approaching 

 closely to latter though separate from it; all of nostril, except for a small circular aper- 

 ture at outer end, rooted over by expansion of anterior margin; joint nasal curtain sub- 

 rectangular with rounded corners, about three times as broad as long, extending rear- 

 ward to slightly overlap anterior tooth band; free posterior margin of nasal curtain 

 smooth In large specimens, weakly zigzag in small, or perhaps even irregularly and 

 narrowly fringed, with a low median projection in some preserved specimens; outer 

 half of posterior margin of nostril also expanded as a short rounded flap, directed 

 inward and rearward toward the mouth, its free edge either smooth or irregularly 

 zigzag.1^2 Mouth transverse, straight, its breadth when closed 77—92 "/q as great as 

 distance between orbits and about half as great as distance from anterior margin of 

 upper tooth band to tip of snout. Lips conspicuously fleshy at corners, with many short 

 wrinkles. Tooth bands occupying about 60 % of breadth of mouth when closed, the 

 extreme length from front to rear of exposed portion of upper band about half as great 

 as its transverse width from one end to the other; length of lower band from front to 

 rear only about Va as great as Its transverse width. 



Teeth Increasing in number of series with growth from about J^ in specimen 

 239 mm long to about 33 in adults; with single conical cusp that is rather sharp; closely 

 crowded; posterior teeth considerably longer than anterior ones, a difi:erence probably 

 resulting from wear; seven to eight rows in function simultaneously on both upper 

 and lower tooth bands. 



First and second dorsals approximately equal in size and similar in shape on any 

 given individual; outlines characteristic of young (Fig. 25D) persisting to maturity 

 with little If any alteration in some though changing with growth in others to more 

 narrowly ovoid, with loss of basal recurvature (Fig. 2 5 A); anterior margins a little 

 less than twice as long as bases. Origin of first dorsal posterior to posterior ends of 

 bases of pelvlcs by a distance a little more than half as great as length of its own base. 

 Interspace between first and second dorsals about 36—74 % as long as base of first 

 dorsal. Distance between second dorsal and caudal 43—65 % as long as base of second 

 dorsal. Caudal subtriangular, nearly equilateral; its posterior margin approximately 

 vertical, moderately and continuously convex in small specimens but becoming less 

 so with growth until nearly straight in adults ; upper posterior corner abrupt, the lower 

 corner somewhat more rounded; axis little raised; depth of caudal below tip of axis 

 about equal to height above latter; Its upper margin about as long as distance from 

 origin of first dorsal to origin of second dorsal, or a little longer. Pelvics originating 

 below axils of pectorals, which slightly overlap them; their anterior margins In both 

 sexes about 50—55 "/o as long as distance from origin of pelvics to rear tip and varying 



132. We have seen one specimen in which it is smooth on one side, zigzag on the other. 



