2 I o Memoir Sears Foundation for Marine Research 



a more or less naked band. Alar spines of adult males in two rows, about 15 in each 

 row. Lower surface entirely smooth. 



Snout in front of orbits about 4.4—4.6 times as long as distance between orbits, 

 its length in front of mouth about 1.3 times as great as distance between nostrils. Orbits 

 in young about 80 "/o as long as distance between them and about 1.8 times as long as 

 spiracle; in adults, about 47-51 ",'0 as long as distance between them and about i.i— 1.3 

 times as long as spiracle. Nasal curtain deeply fringed; expanded posterior (outer) 

 margin of nostril either smooth or slightly jagged. Mouth slightly more bowed in adult 

 males than in females. 



Teeth 3!"^, alike in both sexes, long and needle-pointed on broad bases and 

 loosely spaced in transverse series. 



Dorsal fins close to tip of tail, about equal in size, the apex of first dorsal pointed 

 (a characteristic feature), that of second dorsal more rounded; the two dorsals either 

 confluent or separated by a short interspace, sometimes with 1-2 intervening thorns 

 in small specimens but not in adults. Caudal membrane so low as to be distinguished 

 only with difficulty. Pelvics deeply concave outwardly, the indentation scalloped in some 

 specimens but not in others; anterior margin about 45-55 "/o as long as distance from 

 its own origin to rear tip of pelvic; anterior lobe slender, with rounded tip, including 

 only two radials besides the first stout one; posterior lobe moderately convex, its tip 

 narrowly rounded or subangular. 



Anterior rays of pectorals extending forward about 55-70 "/o of distance from 

 level of fronts of orbits toward tip of snout. 



Color. Upper surface dark mouse gray, dark blue gray, or dark brown, either uni- 

 form or irregularly marked with small indefinite rounded spots, light or dark; outer 

 posterior margins of pectorals dusky, margins of pelvics narrowly so. Lower surface of 

 medium-sized and large specimens variegated white and sooty in variable patterns, some 

 chiefly white below with more or less symmetrical dark markings, others chiefly dark 

 with white areas confined to head, and still others intermediate. For typical patterns, 

 see Fig. 44. Small specimens either lack dark markings at first ^i or may already show 

 various small blotches on disc, pectorals and tail.^^ 



Relationship to Other Species. It has been suggested that R. badia Garman 1899, 

 taken at 1,270 fathoms in the Gulf of Panama (Lat. 7°05' N, Long. 79°4o' W) by the 

 Albatross, may be identical with R. hyperborea.^^ However, our own examination of the 

 type (and unique) specimen of R. badia shows that, while it agrees closely in its dermal 

 armature with R. hyperborea^ its axis of greatest breadth is much farther rearward (only 

 a little anterior to the level of the axils of its pectorals) than in R. hyperborea, and the 



21. Jensen, Mindeskr. Steenstr. Fods. Kbh., 2 (30), 19 14: 21. 



22. The two small specimens we have seen are plain-colored below, but they are so evidently stained that we cannot 

 say whether they were white or uniformly gray originally. One 180 mm long from the Faroe-Shetland Channel 

 was yellow below, the pelvics and cloaca tinged with violet (Koefoed, Rep. Sars N. Atlantic Deep Sea Exped., 

 4 [i], Zool., 1927: 24), and one 160 mm long from the Barents Sea is described as yellowish-white below, marked 

 with dark spots behind the mouth, along the margins of the trunk, on the posterior portions of the pectorals, and 

 on the tail (Thielemann, Wiss. Meeresuntersuch., Abt. Helgoland, N. F. 13, Heft 2, 1922: 197). 



23. Berg (Faune Russie, Poiss., J, 191 1 : 103) includes R. badia with query in the synonymy of R. hyperborea. 



