354 THE PLAGIOSTOMIA. 



Raia isotrachys. 



Raia isotrachys Gunth., 1877, Ann. mag. nat. hist., ser. 4, 20, p. 434; 1887, Challenger rept., Zool., 22, 

 p. 7, pi. 3. 



In the figure of the type the anterior angle is nearly 90° and includes the 

 forward two thirds of the disk. Snout elongate, pointed, about two and one 

 half times the width of the mouth. Anterior margins very long, outer margin 

 short. Forward ends of pectorals narrow, elongate, and, in the figure, reaching 

 the tip of the snout. Outer and hinder angles rounded. Mouth small; teeth 

 small, sharp. Tail little longer than the body, extended behind the second 

 dorsal. Back and top of tail rough with minute stellate-based spines. No spines 

 on the superciliary margins. A small spine on the middle of the back ; a series of 

 stronger ones (18) along the median line of the tail, none on the sides. 



Upper parts brownish grey; lower smooth, brownish black. 



Snout to vent 10, length of snout 3, tail 12?, and width of body 13 inches. 



South of Japan in 365 fathoms (Challenger Station 235). 



Raia reversa. 



Rata reversa Lloyd, 1906, Ann. mag. nat. hist., ser. 7, 18, p. 311; 1908, 111. zool. Investigator, Fishes, 

 pi. 39, pi. 41, f. 2. 



Disk rhomboid, width little greater than the length without the ventrals, 

 anterior margins sinuous, indented, front angle about 80°, snout produced blunt, 

 outer and hinder angles and hind margins broadly rounded. Interorbital width 

 four times in length of snout from eye or mouth. Spiracles as large as the eyes. 

 Mouth arched, in width half the length of the snout. Teeth in 42 rows, median 

 long, curved, with cordate bases. Skin over the skull and near the margins of 

 the pectorals, except posteriorly, roughened by spinules; none on the snout. 

 A group of larger spines opposite the eye on each pectoral, a stellate spine in 

 front of and one or more behind each eye, three spines above the gills in a triangle 

 with apex median behind the head, a median series, somewhat interrupted from 

 shoulder girdle to dorsal, and a lateral row about twice as numerous at each side 

 of the median on the tail; sides of tail spinose. Lower surfaces smooth. Dorsals 

 in contact. Two rows of tenacula (male). Body soft and flabby. 



Back white shading into dark grey at the margins, ventrals grey; lower 

 surfaces black. 



Type a male of 24 inches (60 cm.) in length, and about 13 inches (33 cm.) 

 in greatest width, from the Arabian Sea, off the Baluchistan Coast, in 820 

 fathoms. 



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