2o6 Memoir Sears Foundation for Mari?ie Research 



New Jersey); Longley and Hildebrand, Pap. Tortugas Lab., 535, 1941 : 4 (depth, ofFTortugas, Florida); 



Hildebrand, Copeia, 1941 ". 222 (listed, N. Carolina). 

 Raia ackleyi ornata Goode and Bean, Smithson. Contr. Knowl., JJ, 1895 : pi. 7, fig. 24; also Mem. Harv. Mus. 



comp. Zool., 22, 1896: pi. 7, fig- 24 (ill.). 

 Raja garmani Whitley, Aust. Zool., 9, 1939: 248 (^garmani proposed to replace ornata Garman, preoccupied 



by ornata Agassiz, L. [Poiss. Foss., J, 1843: 372, pi. 37, fig. 34] for a fossil Skate). 



Raja hyperborea Collett 1878 



Arctic Skate 



Figures 43, 44 



Study Material. Males, 103 and 445 mm wide, and female, 138 mm wide, from 

 Faroe Channel, 607 fathoms (British Museum [Natural History]); six specimens, 

 male and female, 600— 850 mm long, including two with fully formed claspers, from 

 Ivigtut Fjord (about Lat. 61° N) near Julianehaab, Southwest Greenland (Harv. Mus. 

 Comp. Zool., Nos. 36548 to 36553). 



Distinctive Characters. R. hyperborea resembles R.jenseni (p. 2 1 6), R. lintea (p. 232), 

 and R. radiata (p. 255) in its noticeably short tail and in its mid-dorsal row of stout 

 thorns which extends from the nuchal region to the first dorsal fin, the thorns close 

 posterior to the pelvic girdle being much larger than any other thorns farther rearward 

 along the tail. But it differs from R. radiata by its more numerous (22-31) mid-dorsal 

 thorns; from R. lintea by its fewer thorns (47—51 in R. lintea) and by its shorter and 

 more obtuse snout (cf. Fig. 43 with 49); and from R.jenseni by its fewer teeth (about 

 38-44 series in upper jaw in R. hyperborea., 58-66 series in R.jenseni) and by the 

 development with growth of large thorns on the posterior parts of the pectorals and on 

 the outer anterior parts of the disc (prickly only in R.jenseni). Young specimens resemble 

 young R.fyllae in general appearance, but they are separable from them by their shorter 

 tails, more pointed snouts and lozenge-shaped discs. The subarctic range of R. hyper- 

 borea in the Atlantic lends special interest to the fact that it seems clearly separable 

 from all of the Skates that have been reported from the Bering Sea-Northeast Siberian 

 region. Among these it appears closest to R. rosispinis Gill and Townsend 1897 in num- 

 ber and arrangement of large thorns. But the skin of the disc (mostly smooth in R. hy- 

 perborea apart from thorns) is described as largely prickly in R. rosispinis.^" Nor does 

 R. hyperborea have any close counterpart in boreal-subantarctic latitudes of the South 

 Atlantic, as have R. radiata and R. spinicauda. 



Description. Proportional dimensions in per cent of total length. Female, 8 10 mm 

 (Harv. Mus. Comp. Zool., No. 36549). Male, 850 mm (Harv. Mus. Comp. Zool., 

 No. 36553), from Ivigtut Fjord, Southwest Greenland. 



Disc: extreme breadth 76.5, 75.0; length 55.6, 54.3. 



Snout length: in front of orbits 14.3, 13.5; in front of mouth 13. i, 14.6. 



Orbits: horizontal diameter 3.1, 3.0; distance between 6.0, 6.5. 



20. The original account of R. rosispinis (Gill and Townsend, Proc. biol. Soc. Wash., 11, 1897; 231) is brief and 

 without illustration. 



