2 88 Memoir Sears Foundation for Marine Research 



Second dorsal fin: vertical height 1.5, 1.4; length of base 4.0, 3.6. 



Pelvics: anterior margin 10.7, 11.8. 



Distance: from tip of snout to center of cloaca 35.6, 35.7; from center of cloaca 



to 1st dorsal 48.0, 47.0; to tip of tail 64.4, 64.3. 



Interspace between: ist and 2nd dorsals 4.5, 5.0; 2nd dorsal and tip of tail 3.5, 4.0. 



Disc about 1.2 times as broad as long, snout projecting only slightly on newborn 

 specimens but more conspicuously on larger ones, tip narrowly blunted; maximum 

 anterior angle in front of spiracles about 1 15° on small specimens, about 100° on larger; 

 anterior margins weakly convex anterior to orbits, thence nearly straight to the broadly 

 rounded outer corners; posterior margins evenly and moderately convex, posterior 

 corners broadly rounded, inner margins straight toward axil. Axis of greatest breadth 

 about 75 "/o of distance back from tip of snout toward axils of pectorals. Tail slender, its 

 lateral folds narrow and confined to posterior two-thirds, widening rearward to opposite 

 second dorsal; its length to first dorsal about 1.4 times as great as distance from center 

 of cloaca to tip of snout and about 1.8 times as great to tip in large specimens; a little 

 longer relatively in smaller specimens. 



Upper surface around posterior margins of pectorals and on tip of snout smooth, 

 disc and tail rough elsewhere with small and sharp close-set prickles, many of them 

 covered over with pigmented skin; inner margin of orbit to inner end of spiracle with 

 a single series of small thorns, 7—8 on small and 12—15 ^^ older specimens; 2—3 thorns 

 inward from each spiracle; two on each shoulder of young increasing to 2,—^ on older 

 ones; midline of back with a row of thorns — about six from nuchal region to pectoral 

 girdle, then a gap followed by about 60 smaller thorns along posterior part of disc 

 and on tail to first dorsal fin; thorns in midline paired here and there side by side and 

 more widely spaced rearward, decreasing in regularity with growth; an additional 

 irregular band of small thorns on either side of posterior part of mid-dorsal ridge from 

 about opposite axils of pectorals rearward, losing its identity among prickles of tail; 

 also a row of small thorns along lower edge of tail on either side to a little in advance 

 of first dorsal; anterior two-thirds of dorsals as well as interspace between them prickly, 

 but caudal membrane smooth; pelvics prickly except at margins. Alar spines of adult 

 male not seen. Lower surface of disc and pelvics smooth; tail also smooth below on 

 very young specimens but more or less roughened with prickles on larger specimens. 



Snout in front of orbits about three times as long as orbit on young, about two 

 times on older specimens; its length in front of mouth 2.0—2.3 times as great as distance 

 between exposed nostrils. Orbit about 1.6—2.6 times as long as spiracle; about 1.2— 

 1.5 times as long as distance between orbits on young specimens, about two times on 

 largest specimen seen. Distance between first gill openings 1.7 times as long as distance 

 between exposed nostrils, between fifth gill openings i.o times; first gill openings 

 about as long as fifth and about 25 "/o as long as breadth of mouth. Nasal curtain smooth- 

 edged, posterior (outer) margin of nostril with a few marginal lobelets about midway 

 of its length. Mouth slightly arched centrally. 



