Fishes of the Western North Atlantic 309 



Upper surface of disc conspicuously rough; medium-sized thorns scattered along 

 rostral ridge; about 10 around anterior and inner margins of orbit on largest specimen, 

 fewer on smaller, sometimes one large thorn close in front of orbit ;i^ one to two large 

 thorns inward from spiracle; a few small thornlets in space between eyes on small speci- 

 mens; a patch of 12-15 conspicuous thorns near outer margin abreast of eye and spir- 

 acle; 1—3 conspicuous thorns on midline in nuchal region; inner parts of pectorals with 

 many moderate-sized thorns irregularly distributed, progressively smaller outward, 

 posterior margins of pectorals smooth; 2—3 large thorns on each shoulder; also a band 

 of thorns of various sizes along midbelt of back from nuchal region rearward, irregularly 

 scattered to anterior part of tail but arranged partially in 3—5 rows back along tail to 

 first dorsal, and successively smaller along rear half of tail, followed by 1—2 rows 

 of smaller ones along either side of tail to tip; thorns on disc and some of those on tail 

 large and their bases conspicuously radiate. Some small specimens lacking the pair of 

 thorns between the spiracles, but with thorns more numerous along midbelt of disc and 

 more nearly linear in arrangement, including a definite median row of about 25 along 

 tail, besides 1-2 less regular rows along either side of tail. Disc as a whole (except 

 above body cavity and around posterior margins of pectorals) further roughened by 

 prickles of various sizes, these more numerous on small specimens than on large; skin 

 above eyes with a few small prickles on large specimens, more prickly on smaller ones ; 

 each side of tail with a band of close-set prickles extending along anterior two-thirds on 

 young but confined to anterior third of tail on larger specimens, followed rearward by 

 scattered small thornlets; space between orbits more prickly on young than on adults; 

 anterior parts of dorsals prickly, decreasingly so with growth; caudal membrane with 

 a few scattered prickles; pelvics smooth. Alar thorns of adult male not seen. Lower 

 surface smooth, except sometimes with a few small spines along edges of tail abreast 

 of posterior lobes of pelvics.^* 



Snout in front of orbits about 1.5— 1.7 times as long as orbit, its length in front 

 of mouth about 1.5— 1.7 times as great as distance between exposed nostrils. Orbit about 

 1.3— 1.7 times as long as distance between orbits and about 1.5 times as long as spiracle. 

 Distance between first gill openings 2.3—2.7 times as long as distance between exposed 

 nostrils; between fifth gill openings 1.3 — 1.5 times; first gill openings i. 0—1.5 times as 

 long as fifth and about 18—27 % ^s long as breadth of mouth. Nasal curtain fringed, 

 posterior (outer) margin of nostril either fringed or only somewhat irregular. Mouth 

 weakly arched centrally. 



Teeth j^lllf on specimens seen, perhaps more numerous on adults; those of 

 females close-set in quincunx, the older rows worn smooth, the younger with low 

 triangular cusp; teeth of adult male not seen. 



First and second dorsals similar in size and shape, confluent at base, their upper 

 margins noticeably sloping, their posterior margins slightly recurved. Caudal mem- 

 brane posterior to second dorsal a little less than half as long as base of second dorsal. 



15. This is true of one of the fragmentary specimens from the offing of Delaware Bay; see Study Material, p. 307. 



16. On our larger specimen one side of the tail but not the other has these spines. 



