476 Memoir Sears Foundation for Marine Research 



spaced, but not overlapping, varying considerably in shape on different parts of the body 

 and at different agesj in the adult, those on upper sides along midsector of trunk lanceo- 

 late, sharp-tipped, with very high median crest dividing anteriorly into 2 or 3 definite 

 ridges, and with a broad wing-like expansion either side opposite the median axis of the 

 pedicel ; farther forward, on the trunk, and also rearward and downward, these give place 

 to flatter forms without lateral wings, those on top of snout being ovoid, those on anterior 

 margins of pectoral and dorsal fins either ovoid or lanceolate, with the primary median 

 ridge dividing anteriorly into 2 or 3; those on sides of caudal peduncle either evenly 

 ovoid or weakly tridentate, with 3 separate longitudinal ridges; those on lower surface 

 generally lanceolate, the median ridge either simple or dividing into 2 anteriorly. 



Head a little more than V4 (about 28%) of trunk to origin of caudal, its dorsal out- 

 line weakly convex to eye, but flat or slightly concave thence forward. Snout thicker at tip, 

 more broadly ovate and relatively shorter than in acanthias, its length in front of nostrils 

 about Vs its length in front of mouth, and the length in front of mouth only a little more 

 than V3 (about 39 to 40%) of length of head. Eye oval, its outline more convex below 

 than above, its horizontal diameter about V2 as long as snout in front of mouth (only about 

 Vs that long in acanthias) or about as long as distance between nostrils. Spiracle about V4 

 as long as horizontal diameter of eye, about on a level with upper margin of eye and behind 

 latter by a distance about Vs as long as horizontal diameter of eye. Gill openings low down 

 on the sides, the 5th slightly the longest, about V2 as long as horizontal diameter of eye 

 and 1.3 times as long as ist. Nostril very slightly oblique, a little more than V2 as long as 

 horizontal diameter of eye, its inner end nearer to tip of snout than to mouth by a distance 

 % to % as long as horizontal diameter of eye, its inner margin expanded as a broad, sub- 

 triangular lobe, which may or may not have a small subsidiary lobe."' Mouth only very 

 slightly arched, occupying about % of breadth of head. Upper labial furrow about V2 as 

 long as diameter of eye and running obliquely forward, the lower furrow less than % 

 as long as upper. 



Teeth }|^Er|) so closely resembling those of acanthias that the illustration (Fig. 

 89 C) is sufficient, i or 2 series functional, depending on the stage in the process of replace- 

 ment. 



First dorsal somewhat less sloping than in acanthias, its extreme length from origin 

 to rear tip about twice its vertical height (about 2.3 times in acanthias), its vertical height 

 about Vs as great as length of head, its origin a little anterior to midpoint of inner margins 

 of pectorals, its spine reaching nearly to apex in male and apparently in female also, its an- 

 terior margin weakly convex, posterior margin only slightly concave, its apex broadly 

 rounded, the free rear corner about as long as base or a little shorter, the midpoint of base 

 only about ^z as fatirom axil of pectoral as from origin of pelvics. Interspace between ist 

 and anddorsHsaboutaslong as from tip of snout to axil of pectoral. Second dorsal about 



59. In the adult male specimen (the type), the left-hand nostril lacks this lobe, but it is present on both nostrils in 

 the female specirhen~(Fig. 89 B). 



