Fishes of the JVestern North Atlantic 



219 



Figure 47. Raja laevis. A Dorsal view of female, 1,187 mm long, from off Massachusetts (Harv. Mus. Comp. 

 Zool., No. 368). B Ventral view of another female, 676 mm long, from Nantucket Shoals (Harv. Mus. Comp. 

 ZooL, No. 36302), to show pigmented mucous pores. C Nasal curtain of same, about 2.6 X . T> Nostril of same, 

 about 2.6 X. E Upper teeth from center of jaw of female, 1,265 mm long, from Nantucket Shoals, about 3.5 X. 

 F Teeth from center of jaw of male, 1,320 mm long, from Nantucket Shoals (Harv. Mus. Comp. ZooL, 

 No. 36264), about 3.5 X; symphysis marked by dotted line. 



Among Skates of the Pacific Coast of North America, the closest counterparts to 

 R, laevis are R.rhina Jordan and Gilbert 1880, also with pigmented mucous pores, 

 and R. binoculata Girard 1854, both of which range from southern California to Alaska. 

 However, the anterior margins of R. rhina are much more deeply concave than are 

 those of R. laevis^ and the snout of the former is narrower and considerably longer 

 relatively (snout in front of mouth about 4 times as long as distance between orbits 

 in R. rhina\ only about 2.5-3 times in R. laevis)^ to mention only the more obvious dif- 

 ferences. R. binoculata has two large orbital thorns and one large mid-dorsal thorn on 

 the nuchal region when young but only one row of thorns (in addition to prickles) 

 along the tail when adult; the mucous pores on its lower surface are not pigmented; 



