Fishes of the Western North Atlantic 459 



widest near corners of mouth; either i or 2 series in function all along each jaw, or per- 

 haps even 3, depending on their stage in the process of replacement.'"' 



Length of ist dorsal from origin to rear tip nearly 2.3 times its vertical height, which 

 is only a little more than V4 of length of head, its origin varying in Woods Hole specimens 

 from about over the inner corner of pectoral to posterior to the latter by a distance about 

 as long as horizontal diameter of eye; the spine a little longer in males than in females 

 (cf. Fig. 87 A with 87 D) and reaching at most to the midpoint of anterior margin of 

 fin, the apex rounded, posterior margin moderately concave, free rear corner a little shorter 

 than base, the midpoint of latter nearer to axil of pectoral than to origin of pelvics. 

 Interspace between ist and 2nd dorsals as long as, or somewhat longer than, head in adult, 

 but only about as long as from tip of snout to 2nd or 3rd gill opening in newborn speci- 

 mens. Second dorsal nearly as long at base as ist but only about % as high vertically, its 

 posterior margin more deeply concave, its free rear corner a little shorter than base, its 

 origin about over tips of pelvics, its spine reaching about % the way to the apex in females 

 but nearly to the apex in males. Interspace between 2nd dorsal and caudal about twice as 

 long as base of 2nd dorsal. Caudal only about ^ the total length, without subterminal 

 notch, its axis only very little raised, its upper margin nearly straight, apex moderately 

 rounded and lower margin somewhat sinuous, the lower lobe about V2 as long as upper, 

 but considerably less than Y2 as large in area with narrowly rounded tip ; the re-entrant 

 contour between the 2 lobes subrectangular with well rounded corner. Pelvics about as 

 long at base as 2nd dorsal, their anterior margins straight or very slightly convex, pos- 

 terior margins moderately concave, tips tapering, subangular, midpoint of base nearer 

 to origin of 2nd dorsal than to rear end of base of ist dorsal by a distance nearly or quite 

 as long as base of latter. Clasper of adult male subdivided at tip into 2 short rounded lobes, 

 the outer soft, the inner cartilaginous, with a sharp recurved hook in its inner edge. Pectoral 

 about tf) as long as head and a little more than V2 as broad as long, the outer margin 

 moderately convex toward apex, distal margin moderately and evenly concave, apex and 

 inner corner rather narrowly rounded. 



Color. Usually slate-colored above, although sometimes tinged with brown; pale 

 gray, grayish white, or pure white below; a row of small white spots irregularly arranged 

 on each side from above the pectorals to abreast of the pelvics, with a few others in front 

 of and behind the first dorsal, as well as close in front of the second dorsal and scattered 

 on the upper sides of the anterior part of the trunk. These spots are most conspicuous in 

 young specimens up to 12 to 14 inches long, fading with growth, and sometimes entirely 

 lacking in large adults. The upper distal margins of caudal and of first and second dorsals 

 are dusky in at least some newborn specimens, but fade with growth. 



Size. Although an occasional Spiny Dog may be born at a length no greater than 

 165-179 mm. (6V2-7 in.), the majority are about 220 to 330 mm. (8%-i3 in.) at 

 birth. It has also been observed that the smaller parent fishes contained smaller embryos 



25. See discussion, p. 65. 



