48 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 119 



anterior to a transverse line drawn between posterior margins of 

 orbits, while in larger individuals a line drawn between these points 

 passes through the symphysis; a weakly marked labial furrow present 

 on lower jaw only, the furrow extending only a short distance (con- 

 cealed when mouth is closed) . 



Fourth gill slit situated anterior to, and fifth gill slit slightly pos- 

 terior to, insertion of pectoral fin; posterior lobe of first dorsal fin 

 terminating just anterior to insertion of pelvic fin (the dorsal and 

 pelvic fins being in closer proximity only in S. tudes, S. corona, and 

 S. media) ; first dorsal fin relatively slender, not perfectly erect, a 

 line drawn perpendicularly from apex of fin barely intersecting lobe 

 of fin; base of first dorsal fin about two-fifths length of head and at 

 least half again length of pectoral fin base; anterior margin of first 

 dorsal fin evenly curved, with the part nearest the apex more strongly 

 curved; distal margin of first dorsal fin moderately falcate; lobe of 

 first dorsal fin from four-ninths to almost one-half length of first 

 dorsal base; origin of second dorsal fin situated about a third of way 

 back above base of anal fin ; second dorsal fin rather tall, its greatest 

 height about two-thirds length of base, and about equal to greatest 

 height of anal fin; second dorsal fin base about five-eighths of anal 

 fin base; lobe of second dorsal fin rather long, its length about a third 

 again greatest height of same fin, and extending about two-thirds 

 of distance from posterior part of second dorsal base to upper pre- 

 caudal pit; anterior margin of pectoral fin from one-half to nearly 

 two-thirds length of head (higher values usually apply to larger 

 individuals); pectoral fin four-fifths as broad as long; pectoral fin 

 base five-eighths to three-fourths length of anal fin base; anterior 

 margin of pectoral moderately convex; distal margin of pectoral 

 nearly straight; apex and inner corner of pectoral rounded; pelvic 

 fin about three-fourths length of anal fin; pelvic fin base about three- 

 fourths length of anal fin base; anterior margin of pelvic fin weakly 

 convex; distal margin of pelvic fin very shallowly falcate; anal fin 

 about one-fourth again as long as pelvic fin; anal fin base from one- 

 fourth to over one-third again as long as pectoral and pelvic fin 

 bases, and from three-fifths again to nearly twice as long as second 

 dorsal fin base; height of anal fin about equal to greatest height of 

 second dorsal fin; anal fin weakly falcate toward apex and nearly 

 straight toward tip of lobe; caudal fin from one-fourth to nearly 

 one-third of total body length; upper margin of caudal nearly straight; 

 terminal part of caudal about one-fourth of total length of fin; posterior 

 margin of terminal part of caudal fin nearly straight or shghtly 

 falcate; both terminal and lower apices of caudal narrowly rounded 

 in smaller specimens, somewhat more pointed in larger individuals; 

 lower caudal lobe appearing relatively broad and short, the distance 



