344 THE PLAGIOSTOMIA. 



closely set hooked scales. A vertebral row of striate-based compressed tubercles 

 from head to second dorsal ; a single tubercle above each shoulder. No tubercles 

 around eyes or spiracles. Lower surfaces smooth. 



Upper parts uniform slaty brown or leaden with numerous small spots of 

 black ; a light spot on each side of the tail behind the ventrals and a fainter one 

 behind each shoulder on the pectorals. 



Total length 12, tail 6, and greatest width 7 s inches. 



Type secured in Friday Harbour, Washington, by Dr. Trevor Kincaid. 



Raia trachura. 



Raia trachura Gilbert, 1S92, Proc. U. S. nat. mus., 14, p. 539; 1895, Rept. U. S. fish comm. for 1893, 

 p. 398; Joed. & Everm., 1896, Bull. 47, TJ. S. nat. mus., p. 75. 



Disk broader than that of R. isotrachys, snout blunter, front angle greater 

 than 90°, outer angles broadly rounded, anterior margins strongly undulated 

 convex at the snout. Snout angle about 120°. Interorbital space concave, 

 width little more than length of eye, about one third the length of the snout. 

 Teeth small, with a minute cusp. Tail little longer than the body. Upper 

 surfaces sparsely but evenly roughened by small stellate-based spines, which 

 are closer set on the interorbital space, along the anterior margins, behind the 

 shoulders and on the sides of the tail. No tubercles on the orbital ridges or 

 the shoulders; a single small tubercle on the middle of the back, above the 

 shoulder girdle, and a median series of tubercles on the tail. 



Back plumbeous, darker at the margins. Lower surfaces brown, lighter 

 on the body, blackish on the margins of pectorals and ventrals. 



Type 18 inches in length, taken in Lat. 32° 40' 30" N., Long. 117° 31' 30" W., 

 in 822 fathoms. 



Santa Barbara Channel, off the coast of southern California. 



Raia abyssicola. 



Raia abyssicola Gilbert, 1895, Rept. U. S. fish comm. for 1893, p. 396, pi. 20; Jord. & Everm., 1896, 

 Bull. 47, U. S. nat. mus., p. 76. 



Disk rhomboid, wider. than long, front angle less than 90°, outer angles 

 greater, rounded, anterior margins nearly straight, hinder broadly rounded. 

 Width of mouth more than half its distance from the end of the snout. Teeth 

 in 31 rows. Eyes small. Tail slender, tapering, little more than half the total 

 length, lateral folds wide. Dorsals separated by a space with a spine. Claspers 

 long, slender, flexible, enlarged at the ends. Tenacula in a band near the outer 



