Fishes of the Western N^orth Atlantic 



55 



6a. Distance from tip of snout to level of fronts of orbits about 

 equal to distance from rear margins of orbits to axils of pec- 

 torals, congolensis Giltay 1928." 



Belgian Congo Coast. 



6 b. Distance from tip of snout to level of fronts of orbits con- 

 siderably less than distance from rear margins of orbits to axils 

 of pectorals. 



Figure 12. Left-hand nostrils, A Rhinobatos rhinobatos, male, about 720 mm 

 long, from Mediterranean (Acad. Nat. Sci. Philad.). B R. lentiginosus. C R. 

 perceUens. D R. horkelii. 



7a. A cluster of 3-4 enlarged tubercles on each shoulder, with 

 one over outer end of pectoral girdle ; snout in front of mouth 

 more than three times as long as breadth of mouth; outer 

 fold on posterior margin of spiracle conspicuously larger 

 than inner fold. horkelii Muller and Henle 1841, p. ^d. 



7b. Only two tubercles on each shoulder and none over outer 

 end of pectoral girdle; snout in front of mouth consider- 

 ably less than three times as long as breadth of mouth; 

 outer fold on posterior margin of spiracle not conspicuously 

 larger than inner fold. 



cemiculus (St.-Hilaire) 18 17 (adult). 

 Mediterranean to tropical West Africa. 



42. R. congolensis may prove to be identical with R. cemiculus. 



