Fishes of the Western North Atlantic 301 



to rear tip of pelvic or a little longer; anterior lobe fleshy, narrow, with abruptly rounded 

 tip, including four radials besides the first stout one; outer margin of posterior lobe 

 scalloped and moderately convex; rear corner subangular, extending about 20—25 "/o 

 of distance trom level of axils of pectorals toward first dorsal. Claspers of mature males 

 slender, extending rearward a little less than '/a the distance from axils of pelvics toward 

 tip of tail; tip of clasper with prominent blade, but otherwise simple. 



Rostral cartilage narrow, blunt, extending about 60 "/o of distance from front of 

 cranium toward tip of snout. 



Color. Upper surface varying from pale yellowish brown to darker greyish brown, 

 purplish brown, or mouse gray; skin at bases of prickles and at rear sides of larger 

 thorns densely pigmented, thus producing a finely freckled appearance; disc irreg- 

 ularly and more or less strongly marked with dark spots or blotches, vaguely outlined 

 and varying from specimen to specimen in size, shape, number, and arrangement; some 

 individuals variegated in addition with a greater or lesser number of small roundish 

 white spots irregularly distributed. Tail with 5—7 irregular dark crossbars, either con- 

 tinuous across upper surface or interrupted there, the two more posterior crossbars 

 usually nearly black and crossing the first and second dorsal fins; tail on some individuals 

 also with whitish lateral blotches, either confined to sides or meeting above; caudal 

 membrane wholly or partly black. Lower surface yellowish white, sometimes with pos- 

 terior corners of pectorals more or less dusky and with dark crossbars encroaching 

 somewhat onto lower surface from sides of tail. 



Size. Males may mature sexually at a length no greater than about 230 mm to 

 judge from the length of claspers (Fig. 67). The largest specimen seen (a female, the 

 type) is 253 mm long. 



Developmental Stages. The egg cases have not been seen. 



Habits. The depths of capture (230—333 fath.) mark this as a deep-water species; 

 nothing else is known of its habits. 



Range. Thus far B. plutonia has been taken only on the continental slope in the 

 offings of Georgia and South Carolina, where the original specimens were trawled by 

 the Blake in i 880,* off northern North Carolina, where it has been taken by the winter 

 trawl fishery, and in the offing of Jacksonville, Florida (see Study Material, p. 297).' 



Synonyms and References: 



Raja^ plutonia Garman, Bull. Mus. comp. Zool. Harv., 8, 1881: 236 (descr., meas., depth, off S. Carolina 

 and Georgia); Goode and Bean, Bull. Mus. comp. Zool. Harv., 10, 1883: 225 (listed after Garman, 

 1881); Jordan and Gilbert, Bull. U. S. nat. Mus., 16, 1883: 878 (descr., after Garman, 1881); True, 



6. Blake Sts. 316, 317, 321; Lat. 3i°57' N, Long. 78°i9' VV; Lat. 32°07' N, Long. 78°38'W; Lat. 32°43' N, Long. 

 77°2i' W. 



7. Kaia plutonia Barnard 1925 (Ann. S. Afr. Mus., 21 [i], 1925: 68) from South Africa, earlier described as K. al- 

 balinea by von Bonde and Swart (Fish. Mar. biol. Surv. S. Afr., Rep. 3 [1922], Spec. Rep. 5, 1924: 6, pi. 20, fig. i), 

 differs noticeably from Brei'iraja plutonia of the western Atlantic in its considerably shorter tail, in larger and 

 fewer thorns around the eyes, and in its pale dorsals. It has been identified provisionally by Norman (Discovery 

 Rep., 12, 1935: 46) with Raia spinacidermis Barnard 1923 (Ann. S. Afr. Mus., 13 [8]: 440), which appears to be 

 closest to the European Raja fullonica Linnaeus 1758. 



8. Sometimes spelled Raia. 



